Most populated artificial bat roost

The world's most populated artificial bat roost is the bat house constructed in March 1991 at the University of Florida, USA. It is occupied by approximately 300,000 insectivorous bats, which can collectively devour at least 2.5 billion insects per night. This is roughly equivalent to 1,100 kg of insects by weight. As described in this bat house's official web page: "It consists of a single gabled roof, the base of which is situated twenty feet above the ground on five wood poles. The house is eighteen feet square and is constructed of exterior grade plywood. To the casual observer it might look like a big attic on stilts. Under the 'attic' there are 180 crevices created by partitions spaced at varying distances of 3/4, 1 and 1-1/4 inches apart. These crevices were designed to provide comfortable living quarters for an estimated 250,000 bats."