Unesco world heritage sites  Spanning continents and countries,
UNESCO World Heritage Sites are notable landmarks or natural
wonders that are of cultural, national or historical
significance. We profile three of the world's best.  The Great
Wall of China Website: http://www.greatwall-of-china.com  The
world's largest military structure, the Great Wall of China,
stretches 8852km from the east to the west of China, spanning
numerous cities. While construction of the Wall started in
220BC, to protect China from northern invasions, it was built by
various dynasties – most of its remains were constructed during
the Ming Dynasty (1368-1644). Today, the Wall provides insight
into Chinese history and is an example of the wonders of ancient
China's military history, culture, architecture and
construction. Various sections of the Great Wall can be visited
and organised tours depart from Beijing daily.  Vredefort Dome
South Africa Website: http://www.domebergland.co.za  South
Africa boasts numerous World Heritage Sites,