A man shops at a hat store at the Namdaemun Market in Seoul, South Korea, May 30, 2017. Picture taken on May 30, 2017. REUTERS/Kim Hong-Ji

A woman shops at the Namdaemun Market in Seoul, South Korea, May 30, 2017. Picture taken on May 30, 2017. REUTERS/Kim Hong-Ji

A street vendor counts his money at the Namdaemun Market in Seoul, South Korea, May 30, 2017. Picture taken on May 30, 2017. REUTERS/Kim Hong-Ji

A worker labours on Namdaemun, officially called Sungnyemun, or "Great South Gate" in central Seoul, South Korea, August 29, 2016. Picture taken on August 29, 2016. REUTERS/Kim Hong-Ji

Workers rest as they labour on Namdaemun, officially called Sungnyemun, or "Great South Gate" in central Seoul, South Korea, August 29, 2016. Picture taken on August 29, 2016. REUTERS/Kim Hong-Ji

Women shops at the Namdaemun Market in Seoul, South Korea, May 31, 2016. REUTERS/Kim Hong-Ji

A woman walks in the Namdaemun Market in Seoul, South Korea, May 31, 2016. REUTERS/Kim Hong-Ji

A street vendor counts his money at the Namdaemun Market in Seoul, South Korea, March 31, 2016. REUTERS/Kim Hong-Ji

A restaurant worker carries a plate on her head as she delivers a food during a lunch time at the Namdaemun Market in Seoul, South Korea, November 24, 2015. REUTERS/Kim Hong-Ji

A woman tries on a woolly hat at a hat store at the Namdaemun Market in Seoul, South Korea, November 24, 2015. REUTERS/Kim Hong-Ji

A shopkeeper naps at the Namdaemun Market in Seoul, South Korea, November 24, 2015. REUTERS/Kim Hong-Ji

A restaurant worker carries plates on her head at the Namdaemun Market in Seoul May 20, 2014. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: BUSINESS EMPLOYMENT)

A man takes a nap at his shoe store at the Namdaemun Market in Seoul May 20, 2014. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: BUSINESS)

South Korean workers gather in front of Namdaemun, officially called Sungnyemun, or "Great South Gate" during a general strike in Seoul December 28, 2013. About 30,000 South Korean workers attend the rally against government decision to set up a unit to run a high-speed bullet train which they say will lead to privatisation and layoffs. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: POLITICS CIVIL UNREST TRANSPORT BUSINESS EMPLOYMENT)

South Korean troops attend a military parade in front of Namdaemun, officially called Sungnyemun, or "Great South Gate" during a ceremony to mark the 65th anniversary of Armed Forces Day on the street in central Seoul October 1, 2013. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY ANNIVERSARY)

South Korean troops attend a military parade in front of Namdaemun, officially called Sungnyemun, or "Great South Gate" during a ceremony to mark the 65th anniversary of Armed Forces Day on the street in central Seoul October 1, 2013. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY ANNIVERSARY)

South Korean troops attend a military parade in front of Namdaemun, officially called Sungnyemun, or "Great South Gate" during a ceremony to mark the 65th anniversary of Armed Forces Day on the street in central Seoul October 1, 2013. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY ANNIVERSARY)

South Korean troops attend a military parade in front of Namdaemun, officially called Sungnyemun, or "Great South Gate" during a ceremony to mark the 65th anniversary of Armed Forces Day on the street in central Seoul October 1, 2013. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: MILITARY ANNIVERSARY)

Shoppers buy vegetables at Namdaemun market in central Seoul September 2, 2013. REUTERS/Lee Jae-Won (SOUTH KOREA - Tags: BUSINESS FOOD)

A South Korean man waves a national flag near the landmark Sungnyemun Gate, or Namdaemun Gate, before its reopening ceremony in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

Performers wearing traditional South Korean dresses march on the street in front of the landmark Sungnyemun Gate, or Namdaemun Gate, after its reopening ceremony in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

Performers wearing traditional South Korean dresses return to their positions after performing at the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

Performers wearing traditional South Korean dresses return to their positions after performing at the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean women wearing the traditional Hanbok march on the street in front of the landmark Sungnyemun Gate, or Namdaemun Gate, during its reopening ceremony in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean traditional gate guards wait to open the gate during the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-hye delivers a speech in front of Sungnyemun Gate, or Namdaemun Gate, during its restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY)

South Korean dancers wait to perform during the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-hye (2nd L) plants flowers with students during the Sungnyemun Gate, or Namdaemun Gate, restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY)

A South Korean traditional gate guard sounds the opening drum during the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-hye, wearing a traditional dress, arrives for the Sungnyemun Gate, or Namdaemun Gate, restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY)

South Korean dancers perform during the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-hye, wearing a traditional dress, stands near participants wearing traditional military uniforms during the Sungnyemun Gate, or Namdaemun Gate, restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY)

South Korean children perform during the reopening ceremony of the landmark Sungnyemun Gate, or Namdaemun Gate, in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

Balloons fly over Sungnyemun Gate, or Namdaemun Gate, during its restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY)

South Korean President Park Geun-Hye (C) arrives in a traditional Hanbok for the reopening ceremony of the landmark Namdaemun gate in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-hye delivers a speech in front of Sungnyemun Gate, or Namdaemun Gate, during its restoration ceremony in Seoul May 4, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, officially opened to the public during the ceremony. REUTERS/Lee Jin-man/Pool (SOUTH KOREA - Tags: SOCIETY POLITICS)

South Korean President Park Geun-Hye (C) walks through the Namdaemun gate in a traditional Hanbok as she arrives for the reopening ceremony of the landmark in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-Hye speaks during the reopening ceremony of the landmark Namdaemun gate (background) in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

South Korean President Park Geun-Hye speaks during the reopening ceremony of the landmark Namdaemun gate in Seoul May 4, 2013. South Korea on Saturday reopened its ancient Namdaemun gate (South Gate) to the public, five years after the historic landmark in central Seoul was destroyed in an arson attack. REUTERS/Kim Jae-Hwan/Pool (SOUTH KOREA - Tags: POLITICS SOCIETY TRAVEL)

An aerial view shows Namdaemun Gate or The Sungnyemun Gate in central Seoul May 3 , 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, will officially open to the public with a restoration ceremony on May 4, 2013, according to local media. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: SOCIETY)

Pigeons fly in front of Namdaemun Gate or The Sungnyemun Gate in central Seoul May 3 , 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, will officially open to the public with a restoration ceremony on May 4, 2013, according to local media. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: SOCIETY)

A worker walks at the Namdaemun Gate or Sungnyemun Gate in central Seoul May 3, 2013. The ancient gate, which was destroyed in an arson attack more than five years ago, will officially open to the public with a restoration ceremony on Saturday, according to local media. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: SOCIETY)

Workers from the Korean Confederation of Trade Unions (KCTU) march past South Korea's "National Treasure No. 1", also known as Namdaemun or Sungnyemun, during a May Day rally in central Seoul May 1, 2013. Thousands of workers who took part in the rally asked for an extensive revision of the labour law and demanded that the government provide temporary workers employment stability by converting their status to full-time workers. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: CIVIL UNREST POLITICS SOCIETY BUSINESS EMPLOYMENT)

A man is reflected in a mirror at a hat store at the Namdaemun Market in Seoul March 8, 2013. Hopes grew in South Korea on April 1, 2013, for a government stimulus package and an interest rate cut, after weak export and import figures and soft price data showed Asia's fourth-largest economy sliding further towards stagnation. Picture taken March 8, 2013. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: BUSINESS TPX IMAGES OF THE DAY)

People walk in front of a giant lantern featuring South Korea's "National Treasure No. 1", also known as Namdaemun or Sungnyemun, on the eve of the Seoul Lantern Festival 2012 at Cheonggyecheon in central Seoul November 1, 2012. The festival, running from November 2 to 18, will interpret the theme "Seoul's Roots, the Lifestyles of Our Ancestors", highlighting Seoul's 2,000 year-old history and many traditions. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: SOCIETY)

A worker carries stacks of boxes on his back at the Namdaemun Market in Seoul October 26, 2012. South Korea's economy grew by 0.2 percent in the July-September period from the previous three-month period, the slowest quarterly growth since the fourth quarter of 2009 in Asia's fourth-largest economy. The median forecast called for a 0.1 percent expansion. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: BUSINESS EMPLOYMENT)

A firefighter jumps from a tiled roof at Junghwajeon, the main hall of Deoksugung palace, during a fire drill in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Firefighters conduct a fire drill at Junghwajeon, the main hall of Deoksugung palace, in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Firefighters climb ladders during a fire drill at Junghwajeon, the main hall of Deoksugung palace, in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Participants role playing visitors run during a fire drill at Junghwajeon, the main hall of Deoksugung palace, in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

A firefighter jumps from a tiled roof at Junghwajeon, the main hall of Deoksugung palace, during a fire drill in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Firefighters use water hoses during a fire drill at Junghwajeon, the main hall of Deoksugung palace, in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Firefighters carry ladders during a fire drill at Junghwajeon, the main hall of Deoksugung palace, in Seoul February 10, 2009. The drill was carried out on Tuesday in hopes of preventing the damage to cultural properties by fire after the Namdaemun fire. South Korea's 600-year-old gate Namdaemun, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Dancers perform during a traditional religious service marking the first anniversary of the fire on Namdaemun, officially called Sungnyemun or "Great South Gate", in front of the restoration site in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

A woman hangs a piece of paper with her wish for 'perfect restoration of the fire-damaged Namdaemun', officially called Sungnyemun or "Great South Gate", during the first anniversary of the fire in front of the restoration site in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Visitors look at restoration works at the site of the fire-damaged Namdaemun, officially called Sungnyemun or 'Great South Gate', in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Visitors look at restoration works at the site of the damaged Namdaemun, officially called Sungnyemun or "Great South Gate", in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Visitors look at restoration works at the site of the damaged Namdaemun, officially called Sungnyemun or "Great South Gate", in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

A man and his daughter look at restoration works at the site of the damaged Namdaemun, officially called Sungnyemun or "Great South Gate", in Seoul February 10, 2009. The 600-year-old gate, designated as the country's number one national treasure, was burnt down on February 10, 2008 by an arsonist. The site was opened to the public to mark the first anniversary of the fire. REUTERS/Jo Yong-Hak (SOUTH KOREA)

Japan's self-defense army soldiers raise South Korea's national flag in front of a snow sculpture in the shape of South Korea's 'Namdaemun', which was badly damaged by fire in 2008, at a rehearsal for the opening of the 60th Sapporo snow festival, northern island of Japan, February 4, 2009. About 270 snow and ice sculptures are exhibited in the one of Japan's famous winter events which goes on from Feb 5 to 11. REUTERS/Kim Kyung-Hoon (JAPAN)