Introduction to the Thousand Birds Nest: The Thousand Birds Nest is located on the north side of an isolated island in the water. There are tens of thousands of swallows smaller than sparrows, hovering over the island, blocking out the sky and the sun. The north side of the island is a three-dimensional plane naturally carved by the perennial monsoon. There are thousands of small holes of only about five centimeters. These small holes are the "home" of the gray sand swallows.