In this two photo combination picture, the Eiffel Tower with its usual lighting at left, and after the lighting was switched off at right, at the occasion of the Earth Hour, in Paris, France, Saturday March 28, 2015. This Saturday, 28 March 8:30 p.m. local time, individuals, businesses, cities and landmarks around the world are switching off their lights for one hour to focus attention on climate change. (Photo by Remy de la Mauviniere/AP Photo)

A combination picture shows the Brandenburger Tor gate before and during the Earth Hour in Berlin March 28, 2015. (Photo by Hannibal Hanschke/Reuters)

A combination photo shows St. Sava church before and during the Earth Hour in Belgrade March 28, 2015. (Photo by Marko Djurica/Reuters)

A combination picture shows the city hall before and during Earth Hour in Vienna March 28, 2015. (Photo by Heinz-Peter Bader/Reuters)

A combination photo shows the Serbian Parliament building before and during the Earth Hour in Belgrade March 28, 2015. (Photo by Marko Djurica/Reuters)

Combination picture shows the Hungarian parliament building before and during Earth Hour in Budapest, March 28, 2015. (Photo by Bernadett Szabo/Reuters)

A combination picture shows St. Basil's Cathedral before and during Earth Hour in Moscow, March 28, 2015. (Photo by Sergei Karpukhin/Reuters)

A combination picture shows the Stadthalle, where the Eurovision Song Contest will be held in May, before and during the Earth Hour in Vienna March 28, 2015. (Photo by Leonhard Foeger/Reuters)

A combination picture shows Big Ben and the Houses of Parliament before and during Earth Hour in central London March 28, 2015. (Photo by Stefan Wermuth/Reuters)

A combination picture shows the Acropolis hill before and during Earth Hour in Athens March 28, 2015. (Photo by Kostas Tsironis/Reuters)

A combination picture shows the “Puente Nuevo” (New Bridge) in the day, illuminated by artistic lights, both before the Earth Hour, and during the Earth Hour in Ronda, southern Spain, March 28, 2015. The Puente Nuevo is 120 metres (390 feet) high and the gorge of the river divides the city of Ronda. (Photo by Jon Nazca/Reuters)

A combination picture shows the Taipei 101 building before and during Earth Hour in Taipei March 28, 2015. (Photo by Pichi Chuang/Reuters)

A combination picture shows Madrid's Royal Palace before and during the Earth Hour in Madrid March 28, 2015. (Photo by Susana Vera/Reuters)

A combination picture shows the Old Bridge before and during the Earth Hour in Mostar March 28, 2015. The 16th-century bridge was destroyed during the war in Bosnia between 1992-1995, rebuilt and opened again in 2004. (Photo by Dado Ruvic/Reuters)

A combination picture shows the Chhatrapati Shivaji terminus railway station, also known as Victoria terminus, during and before Earth Hour in Mumbai March 28, 2015. (Photo by Shailesh Andrade/Reuters)

Combination picture shows Yintai Centre buildings before and during Earth Hour, when they turn off the red lights on the tops, in Beijing's central business district, March 28, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A combination picture shows London Eye before and during the Earth Hour in central London March 28, 2015. (Photo by Stefan Wermuth/Reuters)

This combination picture shows Yintai Centre buildings before and during Earth Hour, when the red lights on top of the buildings have been switched off, in Beijing's central business district, March 28, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A combination picture shows Hong Kong's central financial district's (from L to R) Bank of China Tower, Cheung Kong Centre, HSBC headquarters, Standard Chartered Bank before and during Earth Hour March 28, 2015. (Photo by Tyrone Siu/Reuters)

Leifeng Pagoda is seen behind the West Lake before Earth Hour in Hangzhou, Zhejiang province, March 28, 2015. (Photo by Chance Chan/Reuters)

Leifeng Pagoda is seen behind the West Lake during Earth Hour in Hangzhou, Zhejiang province, March 28, 2015. (Photo by Chance Chan/Reuters)

People sit near candles during Earth Hour, after lights were turned off in the city of Cali March 28, 2015. (Photo by Jaime Saldarriaga/Reuters)