900 Stewart Avenue is a building in Ithaca, New York, notable for its unique Egyptian Revival architecture, its dramatic placement partway down a cliff, and being the residence of astronomer Carl Sagan. The building is on a ledge approximately 50 feet (15 m) below street level, overlooking Fall Creek and Ithaca Falls. It is one of only two Egyptian Revival buildings in Tompkins County, the other being the Masonic Temple in downtown Ithaca. Due to its unusual location and design, and its forbidding street entrance, it is the subject of frequent local speculation.