NYPL's holdings of real estate and fire insurance atlases dating from the 19th and 20th centuries, showing streets, blocks, tax lots, and land use classifications of New York City's five boroughs and the surrounding metropolitan area. Cartographers and publishers include Perris, Hyde, Hopkins, Bromley, and Sanborn. William Perris (d.1862), an English-trained civil engineer and surveyor, originated the real estate map format. The Perris maps depict Manhattan and Brooklyn in the 1850s-1860s, when the two boroughs were still separate cities. Commonly called "fire insurance maps," these maps show streets, blocks, tax lots, and current use classifications; they also indicate locations of former streams and related natural features, earlier roads, previous land uses, lot lines, and more; their sequencing replicates the original published volumes. The atlases showcase the design and engineering of particular buildings and neighborhoods, as well as the wider social and political history of New York City. The more recent and prolific mapmaker, "Sanborn" has become shorthand for "fire insurance map" to a wide range of map users in local government and the real estate, hazard insurance and related industries, throughout the nation and the world. Aerial maps and topographical surveys are also in this collection.