Afghan farmers cover themselves with a plastic sheet from the rain on the outskirts of Jalalabad, February 24, 2015. REUTERS/Parwiz (AFGHANISTAN - Tags: ENVIRONMENT SOCIETY)

Employees of German car manufacturer Porsche brave the rain as they wait for a statement from their outgoing CEO, Wendelin Wiedeking, during an employee meeting at the Porsche headquarters in Stuttgart, July 23, 2009. Sportscar maker Porsche conceded a months-long power struggle to mass-market rival Volkswagen by axing its CEO and said it would raise at least 5 billion euros ($7.1 billion) in equity as the two prepared for a merger. REUTERS/Kai Pfaffenbach (GERMANY BUSINESS TRANSPORT)

Tourists look at their camera after taking a photograph of the external of the National Aquatics Centre where the Olympic Games Synchronized Swimming Qualification Tournament is held in Beijing April 16, 2008. REUTERS/David Gray (CHINA)

A worker cleans up the National Aquatics Center, also known as the "Water Cube", in Beijing April 7, 2008. Beijing is one of the most polluted cities in the world and, despite a 120 billion yuan ($17.12 billion) clean-up over the last decade, air quality remains a concern for many athletes coming to the Olympics, already a lightning rod for rights protests worldwide. REUTERS/Jason Lee (CHINA)

A worker cleans the National Aquatics Centre, also known as the "Water Cube", in Beijing April 7, 2008. REUTERS/Jason Lee (CHINA)

Children play with an Olympic mascot outside the National Aquatics Centre during the Good Luck Beijing 2008 Swimming China Open, in Beijing February 1, 2008. A blue box beating with a green heart, Beijing's "Water Cube" National Aquatics Centre is the product of design and engineering harmony, and a rising power's desire to announce itself to the world. The $143-million venue for swimming, diving and synchronised swimming at the Beijing Games opened with a test event on Thursday allowing the Chinese capital's residents to ponder the ethereal cuboid structure at close range for the first time. REUTERS/Claro Cortes IV (CHINA) also see GF2E47I0UX101

People walk outside the National Aquatics Centre, nicknamed the "Water Cube", during the Good Luck Beijing 2008 Swimming China Open in Beijing January 31, 2008. A blue box beating with a green heart, Beijing's "Water Cube" National Aquatics Centre is the product of design and engineering harmony, and a rising power's desire to announce itself to the world. The $143-million venue for swimming, diving and synchronised swimming at the Beijing Games opened with a test event on Thursday allowing the Chinese capital's residents to ponder the ethereal cuboid structure at close range for the first time. REUTERS/Jason Lee (CHINA)

A volunteer dressed as a Beijing 2008 Olympic Games mascot stands outside the National Aquatics Centre, nicknamed the "Water Cube", during the Good Luck Beijing 2008 Swimming China Open in Beijing January 31, 2008. A blue box beating with a green heart, Beijing's "Water Cube" National Aquatics Centre is the product of design and engineering harmony, and a rising power's desire to announce itself to the world. The $143-million venue for swimming, diving and synchronised swimming at the Beijing Games opened with a test event on Thursday allowing the Chinese capital's residents to ponder the ethereal cuboid structure at close range for the first time. REUTERS/Jason Lee (CHINA)

People walk out of the National Aquatics Centre, also known as the Water Cube, after the "Good Luck Beijing" Swimming China Open in Beijing January 31, 2008. A blue box beating with a green heart, Beijing's "Water Cube" National Aquatics Centre is the product of design and engineering harmony, and a rising power's desire to announce itself to the world. The $143-million venue for swimming, diving and synchronised swimming at the Beijing Games opened with a test event on Thursday allowing the Chinese capital's residents to ponder the ethereal cuboid structure at close range for the first time. REUTERS/Jason Lee (CHINA)

A Chinese worker sweeps the ground outside the National Aquatics Centre in Beijing January 28, 2008. China officially unveiled its bubble-wrapped National Aquatics Centre, nicknamed the "Water Cube", on Monday, one of the two iconic venues for this year's Beijing Olympics. The imposing rectangular box, clad in a honeycomb of transparent cushions, will host the swimming, diving and synchronised swimming during the August 8-24 sporting spectacular. REUTERS/Claro Cortes IV (CHINA)

Visitors walk past the National Aquatics Centre in Beijing January 28, 2008. China officially unveiled its bubble-wrapped National Aquatics Centre, nicknamed the "Water Cube", on Monday, one of the two iconic venues for this year's Beijing Olympics. The imposing rectangular box, clad in a honeycomb of transparent cushions, will host the swimming, diving and synchronised swimming during the August 8-24 sporting spectacular. REUTERS/Claro Cortes IV (CHINA)

Security guards keep watch during the inauguration ceremony of the National Aquatics Centre in Beijing January 28, 2008. China officially unveiled its bubble-wrapped National Aquatics Centre, nicknamed the "Water Cube", on Monday, one of the two iconic venues for this year's Beijing Olympics. The imposing rectangular box, clad in a honeycomb of transparent cushions, will host the swimming, diving and synchronised swimming during the Aug. 8-24 sporting spectacular. REUTERS/Claro Cortes IV (CHINA)

A woman plays a "Mugen puti-puti", manufactured by Japanese toy maker Bandai Co, in Tokyo November 12, 2007. Stress relief, diet aid, lucky charm: few can resist the allure of bubble wrap and now a Japanese company is finding new reasons to pop till you drop. Picture taken Nobember 12, 2007. REUTERS/Toru Hanai (JAPAN)

Japanese bubble wrap manufacturer Kawakami Sangyo Co., Ltd employee Ayaka Sugiyama shows the company's bubble-wrap calendar named "Puti puti calendar" in Tokyo November 12, 2007. Stress relief, diet aid, lucky charm: few can resist the allure of bubble wrap and now a Japanese company is finding new reasons to pop till you drop. Picture taken Nobember 12, 2007. REUTERS/Toru Hanai (JAPAN)

Japanese bubble-wrap manufacturer Kawakami Sangyo Co., Ltd's heart-shaped bubble wrap sheets are seen in Tokyo November 12, 2007. Stress relief, diet aid, lucky charm: few can resist the allure of bubble wrap and now a Japanese company is finding new reasons to pop till you drop. Picture taken Nobember 12, 2007. REUTERS/Toru Hanai (JAPAN)

A woman points to a heart-shaped bubble, which is one of ten thousand bubbles on a bubble-wrap sheet manufactured by Kawakami Sangyo Co., Ltd, in Tokyo November 12, 2007. Stress relief, diet aid, lucky charm: few can resist the allure of bubble wrap and now a Japanese company is finding new reasons to pop till you drop. Picture taken Nobember 12, 2007. REUTERS/Toru Hanai (JAPAN)