Since thousands of years ago, the kings and the noble of China has been interested to consumed swallow's nest.
Until now the Chinese still consume it because there are a lot of advantage by consuming swallow's nest, for example :
1.  To speed up blood circulation and to refine skin.
2.  Strengthen our lungs
3.  Maintain our health
4.  Also the Chinese have a belief that by consuming swallow's nest can make them to remain young.

Regarding to the history of swallow's nest, usually people take the nest from caves. This way of taking the nest is dangerous to the swallow's habitation and also can destroy their population.
To prevent the swallow's habitation and population uninterupted. We try to multiply the swallow's nest inside a house that we build especially for swallows.