The Ruwanweliseya, Anuradhapura, Sri Lanka
Built by King Dutugemunu, the Ruwanwelisaya was completed shortly after his death in 137 BC. The central stupa was one of the tallest monuments of the ancient world, standing at 103m; taller than the Taj Mahal, and more than twice the height of the Colosseum. At the time of its original construction, however, it was probably half that height, being added to by successive kings. Its circumference is 290m. February 2016.