Plunging and rearing across the hills of northern China for more than 5,000 miles, the Great Wall is one of the most recognisable manmade sights on the planet.
Its oldest sections date back to the 7th century BC, although stretches were added, enlarged and fortified until as late as the 16th century. As a feat of construction its sheer scale means it has few equals.
It was built principally to protect the Chinese Empires of days gone by from invasion from the north, and it stands today as an extraordinary relic of the past. The number of man hours that would have been necessary to build the wall is almost beyond estimate - it's said there were once as many as 25,000 watchtowers, and legend has it that the foundations are partly comprised of the bones of those workers who perished on the job.
The majority of visitors travel to the neatly renovated stretches of wall near Beijing.
Where is it?
In northern China, stretching east-to-west along the country's historical border. The most popular sections are only around 50 miles from Beijing.
What is it?
A series of enormous defensive walls punctuated by watchtowers. It was constructed in different stages across different eras. The lay of the land means it is not one continuous wall.
Best time to visit?
Spring and autumn are both appealing times to visit, avoiding the heat of high summer and the cold of winter.
The main photo-friendly tourist section is at Badaling. Meanwhile, more intrepid travellers can arrange walks on unrenovated, less crowded sections.