An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)

Participants enjoy mud during the 14th Annual Boryeong Mud Festival at Daecheon Beach on July 16, 2011 in Boryeong, South Korea. The mud, which is believed to have beneficial effects on the skin due to its mineral content, is sourced from mud flats near Boryeong and transported to the beach by truck. (Photo by Chung Sung-Jun/Getty Images)

A close up of ornaments of centuries-old idols of Lord Buddha during the Pancha Daan, Five donation, festival in Bhaktapur, Nepal, 30 August 2016. Thousands of Buddhist pilgrims observe the main day of the Pancha Daan also known as a five summer gifts (rice, grain, salt, money and fruits) festival which is observes for world peace and human welfare. (Photo by Narendra Shrestha/EPA)

Festival-goers enjoy the mud during the annual Boryeong Mud Festival at Daecheon Beach on July 18, 2015 in Boryeong, South Korea. The mud, which is believed to have benefical effects on the skin due to its mineral content, is sourced from mud flats near Boryeong and transported to the beach by truck. (Photo by Chung Sung-Jun/Getty Images)

Street art started out as unintelligible words written on concrete walls with spray paint by gang members or silly kids. Now, however, it evolved into a unique form of art that might stun and inspire awe in the onlookers. For example, the artist that goes by the name 1010 specializes in creating optical illusions. His creations look like portals into other dimensions, without any hint that it might simply be a flat concrete wall painted over with multicolored paints. These pieces of art are so good that it is hard not to reach out into these ‘holes’ to find out whether or not they are real. (Photo by 1010)

A cenote is a natural phenomenon, a sinkhole in the Earth’s surface. The Yucatan Peninsula in Mexico has an estimated 7,000 cenotes because it is primarily made up of porous limestone. For millions of years, rainfall slowly ate away at the limestone and a huge system of underground caves and caverns was formed. Many filled with water from rain or from the underground water table. When the roof of a water filled cave collapses, a cenote is born. The water found in a cenote may be fresh water, salt water, or both. Structurally it may be completely open, like a lake, almost completely closed with just a small opening at the top, or somewhere in between.

Taken by photographer, Denis Budkov, 33, the Plosky Tolbachik is one of a cluster of volcanoes located in the Kamchatka Peninsula in the far east of Russia. After taking a lucky group of tourists to the crater of the flat volcano, the Russian photographer managed to get less than 300 metres away from the spurting jets of lava. Photo: The underground entrance to the volcano resembles a scene from the latest Hobbit movie. (Photo by Denis Budkov/Caters News)