The Roosevelt Warehouse, located at 16th & Dalzelle streets is a staple of the Detroit Urban Exploration scene. Acres of rotting, burned books litter the floor of what used to be Detroit's main post office.
As the Post Office moved to a new facility, the Detroit Public Schools took over the building for use as a warehouse. In 1987, the building caught fire, causing millions of dollars in damage to school supplies. The district subsequently abandoned the building, leaving it open to the elements.
The building gained grisly notoriety in January of 2009 when the body of a homeless man was found in a flooded elevator shaft, nearly encased in ice. It took a newspaper reporter several calls before someone would come out to extract the body. Since then, patrols around the warehouse have been increased, and entrances have been boarded up.
Sweet-Juniper has an excellent write-up on the history of the warehouse.