This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

The Boudhanath, (also written Bouddhanath, Bodhnath, Baudhanath or the Khasa Chaitya), is one of the holiest Buddhist sites in Nepal, along with Swayambhu. It is a very popular tourist site. Boudhanath is known as Khasti by Newars and as Bauddha or Bodhnath by speakers of Nepali. Located about 11 km (7 mi) from the center and northeastern outskirts of Kathmandu, the stupa's massive mandala makes it one of the largest spherical stupas in Nepal. Boudhanath became a UNESCO World Heritage Site in 1979.
To what religion is Boudhanath holy?