Boudhanath is a stupa in Kathmandu, Nepal. The stupa's massive mandala makes it one of the largest spherical stupas in Nepal. The Buddhist stupa of Boudhanath dominates the skyline. The ancient Stupa is one of the largest in the world. As of 1979, Boudhanath is a UNESCO World Heritage Site. Along with Swayambhunath, it is one of the most popular tourist sites in the Kathmandu area.