South Korean police officers show their martial arts' skills during the official launch ceremony of the 2012 Seoul Nuclear Security Summit on February 15, 2012 in Seoul, South Korea. The Korean National Police Agency launched a security squad, exclusively established for the successful hosting of the 2012 Seoul Nuclear Security Summit. The 2012 Seoul Nuclear Security Summit will be held in Seoul from March 26-27, 2012. (Photo by Chung Sung-Jun/Getty Images)

An aerial view of a livestock enclosure of the Himba people, in October, 2014, in the Namib Desert, Namibia. A photographer has captured a bird's eye view of the stunning Namib Desert from a paraglider. Theo Allofs travels the world taking stunning pictures of untouched landscapes from a unique perspective. Soaring 300 metres above ground, Theo shot the yellow sand dunes, dry red river beds and remote townships in Namibia. (Photo by Theo Allofs/Barcroft Media)

Mount Sinabung is seen during an eruption from Surbakti village in Karo, North Sumatra, Indonesia, April 20, 2015. The local government is preparing the relocation of residents from three of the villages that were destroyed. (Photo by Tibta Pangin/Getty Images/Anadolu Agency)

Wang Zhengqing, a 74 year old pneumoconiosis patient, smokes his pipe at Yangjia Hospital in Wuyi County, Zhejiang Province, China October 19, 2015. Former miner Wang was diagnosed with the disease, which is caused by dust inhalation, when he was 24 and has lived at Yangjia Hospital for ten years. (Photo by Damir Sagolj/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.

Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

Villager search for a place for the roasted pigs in Dalem Temple at Timbrah Village on February 27, 2014 in Karangasem, Bali, Indonesia. Usaba Dalem is an annual ritual held by the people of Timbrah Village, during this ritual all the villagers will cook roasted pigs and carry them to Dalem Temple as an offering to God and an expression of gratitude for a successful harvest. (Photo by Putu Sayoga/Getty Images)

People take part in a Halloween street party at Lan Kwai Fong on October 31, 2016 in Hong Kong. Halloween, a contraction of All Hallows' Evening, falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Lam Yik Fei/Getty Images)