Jetavanaramaya, Anuradhapura, Sri Lanka

This gigantic stupa was built by the King Mahasena who ruled Anuradhapura between 273 to 301 AD. He built the stupa as a repentance for persecuting the Theravadins and breaking the Mahavihara that had stood at the same spot. When it was built, the stupa was 122 m making it the third tallest building in the world after the pyramids. The current height of 71 m (233 ft) is still quite an imposing sight to behold.