Hong Kong's Mirador Mansions, like the more famous Chungking Mansions a half-block away, is an enormous multilevel slum dwelling which has become a home for enterpreneurs and foreigners of all description. Various businesses, guesthouses, families, food vendors, shops, criminals and shady characters share this 14-story crumbling city-within-a-city on lower Nathan Road in Tsim Sha Tsui, Kowloon.
This little video inspired me to stay at Mirador, and the guy who shot it seems to have had a similar experience with the hostel he booked, although his room seems larger than mine was. Comfort is not the selling point. I would say the single most important feature you're renting here is the use of an air conditioner.