People stroll alongside one of the hills of the Tio Pio park in Madrid, Monday, January 25, 2016. The park is a high viewpoint frequented mostly by locals due to its view of the Spanish capital skyline. (Photo by Francisco Seco/AP Photo)

Veteran racehorse Morestead models the world's first authentic Harris Tweed suit designed for a racing horse, which has been specially commissioned by William Hill to celebrate the opening of this year's Cheltenham Festival on March 15, 2016 in the U.K. (Photo by Joe Pepler/Rex Features/Shutterstock)

This undated photo provided by NOAA in May 2018 shows aurora australis near the South Pole Atmospheric Research Observatory in Antarctica. When a hole in the ozone formed over Antarctica, countries around the world in 1987 agreed to phase out several types of ozone-depleting chemicals called chlorofluorocarbons (CFCs). Production was banned, emissions fell and the hole shriveled. But according to a study released on Wednesday, May 16, 2018, scientists say since 2013, there’s more of a banned CFC going into the atmosphere. (Photo by Patrick Cullis/NOAA via AP Photo)

These kaleidoscopic images showcase the sheer beauty of the mammoth firework displays held across Japan every summer. The Japanese word for fireworks, hanabi, means fire flower, and each year, local governments in Japan throw around 7,000 festivals, or hanabi taikai. Here: Tsuchiura National Fireworks Competition, Tsuchiura City, Ibaraki Prefecture. (Photo by Makoto Igari/Caters News Agency)

A hummingbird is photographed during the National Orchid Exhibition at the Jose Celestino Mutis Botanical Garden in Bogota, Colombia Septermber 20, 2018. Picture taken September 20, 2018. (Photo by Luisa Gonzalez/Reuters)

Graduates dance as they take part in a “Last school bell” ceremony at a school in Minsk, Belarus on May 30, 2018. (Photo by Vasily Fedosenko/Reuters)

A swarm of starlings flies over the Altare della Patria monument (Unknown soldier) in the city centre of Rome during sunset, on November 27, 2018. (Photo by Vincenzo Pinto/AFP Photo)

The town hall with the Mangia tower is seen in Siena, central Italy, January 29, 2016. (Photo by Max Rossi/Reuters)