Stupa is semicircle shaped structure (domed) memorial which contains the relics and remains of Buddha. Stupas are ancient form of mandala. Stupa in Sanskrit means heap or mound-like architectures.  Stupa is called Chorten in Tibetan and now adopted by English. 
 Stupas are sacred places to worship. Stupa is also called Chaitya. However, Chaitya refers to close stupa inside a building. Sometimes, stupa is also referred as Pagoda.

Boudhanath is one of the largest Stupas in the world, located at heart of Kathmandu at Boudha near by ancient entrance from Tibet to Kathmandu. Sankhu is believed to be the old entrance from Tibet to Kathmandu, which is near to Boudhanath Temple. It is located at about 11 km (6.8 miles) from the center and northeastern within Kathmandu municipality. An ancient and smaller stupa of Chabahil Charumati bihar is located just in about the distance of 2.5 kilometers from Boudhanatha.  Charumati Bihar is known as Little Bouddha. 

 The Stupa of Bauddhanath is believed to have the remains of Kassapa Buddha. It has different names in different languages. Newar community of Nepal calls it Khasti, Tamangs call it Jyarung Khasyor and in Nepali it is Bouddhanath. Boudhanath has been listed as world heritage site by UNESCO in the year 1979.  Boudhnath is very popular place for Buddhist holly rituals and popular sightseeing place to all tourists in Kathmandu.