The Texas Medical Center was originally formed from a gift by philanthropist Will Hogg of 134 acres of woods and prairie at the edge of town to the City of Houston. The newly constituted Texas Medical Center Foundation then purchased the site from the city. The buildings represented on the map are the first construction sites on what later would become the largest medical complex in the world. Each of the facilities within the Texas Medical Center has been added to, renovated and expanded many times. Construction work on the hospitals and support centers has provided employment for a large roster of commercial building contractors for several decades. Today, the Texas Medical Center has five major campuses with several adjacent university, hospital, research and government areas, comprising more than 150 structures.