People ride pedal boats on the Vltava river following the coronavirus disease (COVID-19) outbreak, in Prague, Czech Republic, June 22, 2020. REUTERS/David W Cerny 

People stand on the Vltava river bank amid an outbreak of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 29, 2020. REUTERS/David W Cerny 

Birds fly over the Vltava river bank amid an outbreak of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 29, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant on an embankment along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny TPX IMAGES OF THE DAY 

A municipality worker wearing a protective face mask sprays disinfectant on railings along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker wearing a protective face mask disinfects handrails along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant on an embankment along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

A municipality worker in a protective suit sprays a disinfectant on an embankment along the Vltava river to curb the spread of the coronavirus disease (COVID-19) in Prague, Czech Republic, April 1, 2020. REUTERS/David W Cerny 

Women wearing face masks walk on the Vltava river bank as the spread of the coronavirus disease (COVID-19) continues in Prague, Czech Republic, March 30, 2020. REUTERS/David W Cerny 

A woman wearing a face mask rests on the Vltava river bank as the spread of the coronavirus disease (COVID-19) continues in Prague, Czech Republic, March 24, 2020. REUTERS/David W Cerny 

A man wearing a face mask walks on the Vltava riverbank across from Prague Castle in Prague, following the outbreak of coronavirus disease (COVID-19), Czech Republic, March 20, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants arrive for the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

A participant arrives for the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2020. REUTERS/David W Cerny 

A man feeds swans on the Vltava river bank in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

A swimmer participates in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

A swimmer participates in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

Swimmers participate in the annual Christmas winter swimming competition in the Vltava river in Prague, Czech Republic, December 26, 2019. REUTERS/David W Cerny 

People ride a pedal boat on the Vltava River as the sun sets over the Prague Castle in Prague, Czech Republic, September 10, 2019. REUTERS/David W Cerny 

People ride a pedal boat on the Vltava River as the sun sets over the Prague Castle in Prague, Czech Republic, September 10, 2019. REUTERS/David W Cerny 

People ride pedal boats on the Vltava River as the sun sets over the Prague Castle in Prague, Czech Republic, September 10, 2019. REUTERS/David W Cerny 

Tightrope walker Tatiana-Mosio Bongonga performs on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny 

Tightrope walker Tatiana-Mosio Bongonga performs on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny 

Tightrope walker Tatiana-Mosio Bongonga performs on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny TPX IMAGES OF THE DAY 

Tightrope walker Tatiana-Mosio Bongonga walks on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny 

Tightrope walker Tatiana-Mosio Bongonga performs on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny 

Tightrope walker Tatiana-Mosio Bongonga walks on a rope above the Vltava river to open an international circus and theatre festival in Prague, Czech Republic, August 14, 2019. REUTERS/David W Cerny 

People row their boats on the Vltava river in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

People rest on the Vltava river bank in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

People rest on the Vltava river bank in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

A woman rides a bike along the Vltava river bank in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

A man drinks a water as he rows a boat on the Vltava river in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

A woman rows a boat on the Vltava river in Prague, Czech Republic March 21, 2019. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2019. REUTERS/David W Cerny TPX IMAGES OF THE DAY 

Participants arrive for the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2019. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2019. REUTERS/David W Cerny 

A participant takes part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2019. REUTERS/David W Cerny 

Participants take part in the traditional Three Kings swim to celebrate Epiphany at the Vltava River in Prague, Czech Republic, January 6, 2019. REUTERS/David W Cerny