Swayambhunath Pagoda

According to Swayambhu Purana, the entire valley was once filled with an enormous lake, out of which grew a lotus. The valley came to be known as Swayambhu, meaning "Self-Created." The name comes from and eternal self-existent flame (svyaṃbhu) over which a sūpa was later built.
The Bodhisatva Manjushri had a vision of the lotus at Swayambhu and traveled there to worship it. Seeing that the valley can be good settlement and to make the site more accessible to human pilgrims, Manjushri cut a gorge at Chovar. The water drained out of the lake, leaving the valley in which Kathmandu now lies. The lotus was transformed into a hill and the flower become the Swayambhunath stupa.