One of two 9-month old Cheetahs is seen after it was released into a quarantine facility at Zoo Miami on November 29, 2012 in Miami, Florida. The two sub-adult brothers who arrived today were captive-born on March 6th of this year at the Ann van Dyk Cheetah Centre just outside of Pretoria, South Africa. The Cheetahs, after being monitored and examined for a minimum of 30 days to insure that they are healthy and stable, will be featured in Zoo Miami's Wildlife Show at the newly constructed amphitheater and will continue the work of Zoo Miami's Cheetah Ambassador Program by making appearances off Zoo grounds at a variety of venues including schools and civic organizations. (Photo by Joe Raedle)

“These are the astonishing images of the very aptly named door to hell, a fiery crater thats baffled scientist and has been flaming away for more than 40 years. The crater is 230-feet wide and situated near Derweze village in Turkmenistan”. – Caters News. (Photo by William Keeping/Caters News)

The photos were taken at the Piton de la Fournaise volcano on Reunion Island, a French island in the Indian Ocean one of the most active volcanoes in the world. Here: The powerful erupting volcano. (Photo by Luc Perrot/Caters News)

Female panda Tian Tian makes her first appearance in front of the media since arriving from China on December 12, 2011 in Edinburgh, Scotland. (Photo by Jeff J. Mitchell/Getty Images)

Take a look at this stunning photo of Tolbachik, an active volcanic complex on the Kamchatka Peninsula in far eastern Russia. Lava fountains and rivers ran through the area for months after the eruption began with the opening of two Tolbachik fissures in November of 2012. In the midst of this activity, photographers Luda and Andrey (lusika33) took a trip down to see that stunning hell valley on earth. (Photo by lusika33)

99 Steps of Progress is an illustrated series of parodies created by the Paris artist collective known as Maentis that put a clever spin on the famed scientific March of Progress drawing. A new illustration is being released in this series every day for 99 days. T-shirts, prints and more of each design are available to purchase on RedBubble.

People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)

Children in Hiroshima, Japan, wearing masks to combat the odour of death after the city was destroyed by the first atom bomb. (Photo by Keystone/Getty Images). 1945