Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

Ingots of 99.99 percent pure silver are cast at the Krastsvetmet Krasnoyarsk non-ferrous metals plant in the Siberian city of Krasnoyarsk, Russia, June 5, 2015. Krastsvetmet is one of the world's largest players in the precious metals industry. REUTERS/Ilya Naymushin

An employee walks past a rotary dredge working at an open-cast iron ore mine of the Stoilensky mining and concentration plant (GOK), owned by the Novolipetsk (NLMK) steel mill, in the city of Stary Oskol in Belgorod region, Russia, August 4, 2015. (Photo by Maxim Shemetov/Reuters)

A mushroom cloud dwarfs a row of skyscrapers in what looks like a devastating nuclear bomb detonation. But thankfully this is just a spectacular weather-front blasting in from the tempestuous Rocky Mountains near Denver, Colorado, USA. The unbelievable shot is just one of many of the city's skyline taken by photographer Greg Thow. The 49-year-old has also captured equally stunning shots of lightning blasts and arching rainbows – all from the comfort of his balcony. (Photo by Greg Thow/Barcroft Media)

A tractor trailer drives through flash flood waters that overran Skunk Creek, Tuesday, August 19, 2014, in northwestern Phoenix. Flooding from heavy rain in the Phoenix area has forced authorities to close several major roads, including a portion of Interstate 17 about 25 miles north of the city. (Photo by Matt York/AP Photo)

A worker lays rails across the bed of a drained area of a lake used for the production of salt at the Sasyk-Sivash lake near the city of Yevpatoria in Crimea, October 5, 2014. The area has a long tradition of salt production, prepared from salt flats flooded with water from the Black Sea. (Photo by Pavel Rebrov/Reuters)

Few people haven’t heard about the ancient city of Persepolis, which lies at the foot of the Mountain of Mercy (Kuh-I-Rahmat). In ancient times, Persepolis was the capital of the Achaemenid Empire. Regretfully, it was burned by the Greeks in 330 BC after they looted the immense treasure of this city. It is said that Greeks needed 5,000 camels and 20,000 mules to carry all the treasures from Persepolis. The only thing of Persepolis that has survived the wear of time is the ginormous stone terrace 530 by 330 meters adorned by elaborate stone sculptures. It is amazing how intricately detailed some of the sculptures are, despite the fact that they were created many centuries ago.

A woman is assisted by medical personnel during a celebration in the Mission District in San Francisco, California October 29, 2014. The San Francisco Giants beat the Kansas City Royals 3-2 on Wednesday to win their third World Series title in five seasons. (Photo by Robert Galbraith/Reuters)