A man performs ablution using water at an old fountain before performing prayers in the old city of Algiers Al Casbah, Algeria December 3, 2015. The Algiers Casbah is a UNESCO World heritage site that includes the Sidi Ramdane mosque and former fortress, 10 centuries old. Decay from the passing years, as well as earthquake damage in 2003, leads some to consider a move to modern apartments with financial backing from the government. Others refuse to leave a neighbourhood they have called home for decades. (Photo by Zohra Bensemra/Reuters)

A mahout rides an elephant at Tad Sae Waterfall outside Luang Prabang, Laos July 31, 2016. Protected by the United Nations cultural heritage agency UNESCO, Luang Prabang is one of the most alluring places in the region – a city that evokes old-world romance that has gained a reputation as a travellers' Shangri La. (Photo by Jorge Silva/Reuters)

Hugo Belleri (L), a three-year-old boy and the youngest Gilles of Binche, takes part in the parade of Young Gilles of Binche during the carnival event in Binche February 17, 2015. The Binche carnival, a UNESCO World Heritage event, is the biggest and the liveliest annual event in Belgium. Up to 1,000 Gilles parade in the city centre of Binche, wearing a red, yellow and black medieval costume hung with bells and decorated with fluffy lace at the neck, wrists and ankles. (Photo by Yves Herman/Reuters)

“The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim on the northeast coast of Northern Ireland, about three miles (4.8 km) northeast of the town of Bushmills. It was declared a World Heritage Site by UNESCO in 1986, and a National Nature Reserve in 1987 by the Department of the Environment for Northern Ireland”. – Wikipedia

Photo: Visitors walk on the Giant's Causway on March 14, 2012 in Portrush, Northern Ireland. (Photo by Peter Macdiarmid/Getty Images)

Fossilized whale bones are on display outside the Wati El Hitan Fossils and Climate Change Museum, a UNESCO natural World Heritage site, on the opening day, in the Fayoum oasis, Egypt, Thursday, January 14, 2016. Egypt has cut the ribbon on the Middle East's first fossil museum housing the world's largest intact skeleton of a "walking whale" in an attempt to attract much-needed tourists driven off by recent militant attacks. The construction of the much-hyped Fossils and Climate Change Museum was covered a 2 billion euros (2. 17 billion dollars) grant from Italy, according to Italian Ambassador Maurizio Massari. Its centerpiece is an intact, 37-million-year-old and 20-meter-long skeleton of a legged form of whale that testifies to how modern-day whales evolved from land mammals. The sand-colored, dome-shaped museum is barely discernible in the breathtaking desert landscape that stretches all around. (Photo by Thomas Hartwell/AP Photo)

A monarch butterfly rests on the ground at the Sierra Chincua butterfly sanctuary on a mountain in Angangeo, Michoacan November 24, 2016. Angangueo is a town and municipality located in far eastern Michoacán state in central Mexico noted for its history of mining and its location in the Monarch Butterfly Biosphere Reserve. The Monarch Butterfly Biosphere Reserve is a World Heritage Site containing most of the over-wintering sites of the eastern population of the monarch butterfly. (Photo by Carlos Jasso/Reuters)

The Stone Forest or Shilin is a notable set of limestone formations located in Shilin Yi Autonomous County, Yunnan Province, People's Republic of China, near Shilin approximately 120 km (75 mi) from the provincial capital Kunming. The tall rocks seem to emanate from the ground in the manner of stalagmites, with many looking like petrified trees thereby creating the illusion of a forest made of stone. Since 2007, two parts of the site, the Naigu Stone Forest (乃古石林) and Suogeyi Village (所各邑村), have been UNESCO World Heritage Sites as part of the South China Karst.

A visitor walks inside the initiation well at Quinta da Regaleira in Sintra October 6, 2014. Sintra became the first centre of European Romantic architecture in the 19th century, which influenced the development of landscape architecture throughout Europe. It was classified as a World Heritage Site by UNESCO in 1995. Its monuments are visited by more than 1.5 million of tourists every year, according to local media. (Photo by Rafael Marchante/Reuters)