The view shows the snow-covered Mount Pilatus and the medieval Kapellbruecke bridge behind a weekly market in Luzern, Switzerland May 8, 2021. REUTERS/Arnd Wiegmann

The view shows the snow-covered Mount Pilatus behind a weekly market in Luzern, Switzerland May 8, 2021. REUTERS/Arnd Wiegmann

The view shows the medieval Kapellbruecke bridge and the Wasserturm tower in front of the old town of Luzern, Switzerland May 8 , 2021. REUTERS/Arnd Wiegmann

The snow-covered Mount Pilatus is seen behind the medieval Kapellbruecke bridge and the Wasserturm tower in Luzern, Switzerland May 8, 2021. REUTERS/Arnd Wiegmann

The snow-covered Mount Pilatus is seen behind the medieval Kapellbruecke bridge and the Wasserturm tower in Luzern, Switzerland May 8, 2021. REUTERS/Arnd Wiegmann

A green light is seen in front of a cabin for vaccinations at the vaccination center at the Messe Luzern fairgrond, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

Vaccination cabins are seen at the vaccination center of Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

Vaccination cabins are seen at the vaccination center of Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

A vial of Pfizer vaccine against the coronavirus disease (COVID-19) is seen at the Messe Luzern fairground's vaccination center, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

Vials of Pfizer vaccine against the coronavirus disease (COVID-19) are seen at the Messe Luzern fairground's vaccination center, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

Members of the Swiss civil protection receive instructions at the vaccination center of Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

Vials of Pfizer vaccine against the coronavirus disease (COVID-19) are seen at the Messe Luzern fairground's vaccination center, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

A member of the Swiss civil protection stands in front of vaccination cabins at the Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

A general view shows the vaccination center at the Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

A general view shows the vaccination center at the Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

A member of the Swiss civil protection walks in front of vaccination cabins at the Messe Luzern fairground, as the spread of the coronavirus disease (COVID-19) continues, in Lucerne, Switzerland December 23, 2020. REUTERS/Arnd Wiegmann

The Chatsorn's Table restaurant is seen at Buergenstock Hotels & Resort on Buergenstock near Lucerne, Switzerland April 4, 2018. Picture taken April 4, 2018. REUTERS/Arnd Wiegmann

Tourist vessel Titlis anchors in front of the station of the Buergenstock Bahn cog railway on the banks of Lake Lucerne in Kehrsiten, Switzerland April 4, 2018. Picture taken April 8, 2018. REUTERS/Arnd Wiegmann

The Palace Hotel is seen at Buergenstock Hotels & Resort on Buergenstock near Lucerne, Switzerland April 4, 2018. Picture taken April 4, 2018. REUTERS/Arnd Wiegmann

A picture taken with a fisheye lens shows Mount Rigi (L) and the Palace Hotel at Buergenstock Hotels & Resort on Buergenstock near Lucerne, Switzerland April 4, 2018. Picture taken April 4, 2018. REUTERS/Arnd Wiegmann

The Palace Hotel is seen at Buergenstock Hotels & Resort on Buergenstock near Lucerne, Switzerland April 4, 2018. Picture taken April 4, 2018. REUTERS/Arnd Wiegmann

Mount Rigi is seen beside the Palace Hotel at Buergenstock Hotels & Resort on Buergenstock near Lucerne, Switzerland April 4, 2018. Picture taken April 4, 2018. REUTERS/Arnd Wiegmann

Mark Freymuller, CEO of the Hyundai Hydrogen Mobility, attends a news conference for a new hydrogen fuel cell truck made by Hyundai during a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

A sign on a new hydrogen fuel cell truck made by Hyundai is pictured during a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

New hydrogen fuel cell trucks made by Hyundai are pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

A new hydrogen fuel cell truck made by Hyundai is pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

New hydrogen fuel cell trucks made by Hyundai are pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

A new hydrogen fuel cell truck made by Hyundai is pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

A new hydrogen fuel cell truck made by Hyundai is pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

New hydrogen fuel cell trucks made by Hyundai are pictured ahead of a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

A cameraman films before a news conference for a new hydrogen fuel cell truck made by Hyundai during a media presentation for the zero-emission transport of goods at the Verkehrshaus Luzern (Swiss Museum of Transport) in Luzern, Switzerland October 7, 2020. REUTERS/Denis Balibouse

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

An electric powered Candela Seven boat is pictured on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

An electric powered Candela Seven boat is pictured on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat past the historic steam vessel Uri on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel (L), manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel, manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat past the historic steam vessel Uri on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

Christian Vogel (L), manager of W.A.R. Bootbau und Boothandel AG steers an electric powered Candela Seven boat on Lake Lucerne near Luzern, Switzerland September 2, 2020. Picture taken September 2, 2020. REUTERS/Arnd Wiegmann

A security guard stands at the front entrance of the Lucerne Hotel in the Upper West Side in the Manhattan borough of New York City, New York, U.S., August 10, 2020. REUTERS/Carlo Allegri

Customers wait for orders as Britain's Queen Elizabeth is seen during her address to the nation and the Commonwealth on a television amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

A sign is seen as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People embrace as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People drink beers as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People embrace as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People listen to a band play amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People listen to a band play amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People drink beers as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

People wearing face masks hold hands as a band plays amid an outbreak of the coronavirus disease (COVID-19), at Cafe 247 in Lucerne Valley, California, U.S., April 5, 2020. REUTERS/Shannon Stapleton

The medievial Kapellbruecke bridge and the Wasserturm tower are seen in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Pedal boats are seen during sunny spring weather at the dock of a boat rental on the banks of Lake Lucerne in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Folding tables are seen during sunny spring weather on the terrace of a restaurant in front of the medievial Kapellbruecke bridge and the Wasserturm tower in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Daniel Koch, Head of Communicable Diseases Division at the Federal Office of Public Health, listens to Swiss Interior Minister Alain Berset as he addresses a news conference after their visit to a drive-in test center for tests on coronavirus disease (COVID-19) in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Swiss Interior Minister Alain Berset addresses a news conference, next to Daniel Koch, Head of Communicable Diseases Division at the Federal Office of Public Health, after their visit to a drive-in test center for tests on coronavirus disease (COVID-19) in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

A health worker takes a test from a person in a car at a drive-in test center for tests on coronavirus disease (COVID-19) in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Health workers are seen at a drive-in test center for tests on coronavirus disease (COVID-19) in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

Health workers are seen at a drive-in test center for tests on coronavirus disease (COVID-19), next to the sign that reads: "Look ahead, don't turn head!", in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann

A civil defence worker wears a protection mask as he checks the papers of a car driver before she can enter a drive-in test center for tests on coronavirus disease (COVID-19) in Luzern, Switzerland March 31, 2020. REUTERS/Arnd Wiegmann