Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

A girl jumps to touch cherry blossoms in full bloom in Fussa, outskirts Tokyo, Japan, 05 April 2014. Temperatures being very constant made blossoms to keep full bloom for holiday makers. (Photo by Kimimasa Mayama/EPA)

A man watches the huge waves which brakes at the Paseo Nuevo's promenade in San Sebastian, Basque Country, Spain on 11 January 2016 where the wind has reached to 90 km/h and have been registred waves of eight kilometres due to the bad weather. (Photo by Juan Herrero/EPA/EFE)

A Geoffroy's Monk Saki is seen at the Parque de Las Leyendas zoo in Lima, Peru, February 14, 2018. (Photo by Guadalupe Pardo/Reuters)

The UK reality star Charlotte Crosby leaving Lucky Voice karaoke club on March 28, 2018 in London, England. (Photo by Barcroft Media)

A worker sprays disinfectant as sanitization operations against Coronavirus are carried out in the museum hosted by the Maschio Angioino medieval castle, in Naples, Italy, Tuesday, March 10, 2020. (Photo by Alessandro Pone/LaPresse via AP Photo)

A Palestinian man rides a donkey-drawn cart transporting an old car to a scrap yard, in Gaza City on March 15, 2020. (Photo by Mohammed Salem/Reuters)

Carolaine Reis and her son Miguel Alves, residents of the Aglomerado da Serra favela, wear a protective mask against the spread of the new Coronavirus (COVID-19) made by the seamstresses of the Remexe Favelinha studio, in the Aglomerado da Serra favela, on April 13, 2020 in Belo Horizonte, Brazil. Facial masks follow the protocol and guidelines defined by the Ministry of Health. Around 6,000 masks have already been produced. The masks are being distributed to a part of the population and sold throughout the country, in the amount of 5 reais per unit. (Photo by Pedro Vilela/Getty Images)