Swayambhunath stupa is roughly 2,000 years old. It is located on a small, but steep hill, and used to be outside Kathmandu City. It is home of the Adibuddha, the infinite Buddha without beginning and end.
According to the legend Manjushri, a Chinese saint had come to Nepal to pay his respect to Adibuddha. He found a blue flame on lotus in the middle of a huge lake that filled the Kathmandu valley in former times. Manjushri drained the lake with his sword and transferred the blue flame with the lotus on top of Swayambhunath hill.