Engine driver Josef Kowatsch (top L) steers a train through the NEAT Gotthard Base Tunnel during a media visit near the town of Erstfeld August 24, 2015. Crossing the Alps, the world's longest train tunnel should become operational at the end of 2016, consisting of two parallel single track tunnels, each of a length of 57 km (35 miles). (Photo by Arnd Wiegmann/Reuters)

This combination of August 30, 2005 and July 29, 2015 aerial photos shows downtown New Orleans and the Superdome flooded by Hurricane Katrina and the same area a decade later. Katrina's powerful winds and driving rain bore down on Louisiana on August 29, 2005. The storm caused major damage to the Gulf Coast from Texas to central Florida while powering a storm surge that breached the system of levees that were built to protect New Orleans from flooding. (Photo by David J. Phillip/Gerald Herbert/AP Photo)

March 28, 1967. Egg Roll; A large bunny attracted the attention of children and their parents during the annual Easter egg roll Monday on the south lawn of the White House. The bunny was made by Fred Johansen, Silver Spring, Md. Nearly 17,000 youngsters and adults took part in the egg rolling. The President and Mrs. John-son were not at the festivities because they were in Camp David, Md. The tradition of egg rolling was begun in 1878 during the administration of Rutherford B. Hayes. (Photo by Minneapolis Star Tribune)

The waning moon is setting over the mountain “Les Cornettes de Bise” located at the border of the Haute-Savoie and the Valais canton of Switzerland in the Chablais Alps, photographed from Glutieres, January 7, 2015. (Photo by Anthony Anex/EPA)

Online hostess Xianggong (L) and other hostesses check their pictures as they gather around the photographer while taking part in a football-themed photoshoot at a photography studio in Beijing March 4, 2015. In China's online hostessing world, men find virtual company and the women can find riches. Xianggong is one of more than 10,000 hostesses on the internet site bobo.com, a live broadcasting web platform where anyone can record themselves singing, playing piano, dancing or just chatting. (Photo by Jason Lee/Reuters)

General atmosphere on Shipyard Island, the venue of the 24th Sziget (Island) Festival in Northern Budapest, Hungary, 14 August 2016. (Photo by Mohai Balázs/Rockstar Photographers)

Stingray City is a series of shallow sandbars found in the North Sound of Grand Cayman, Cayman Islands. It is a tourist attraction, where southern stingrays are found in abundance and visitors can pet and interact with the animals.

People attend the 49th annual New York City Gay Pride Parade in New York, New York, USA on 24 June 2018. (Photo by Erik Pendzich/Rex Features/Shutterstock)