NYC developer Julian Boilen's 2020 interactive map puts the NYC Municipal Archives' 1939-1940 tax-assessment building photos onto a street-view-style tool — free, still maintained, and circulating widely again as of July 2026.

A 2020 project by NYC developer Julian Boilen is circulating widely again: navigate to 1940s.nyc, drop a pin anywhere in the five boroughs, and the site pulls up the black-and-white street-level photograph a city tax assessor took of that building in 1939 or 1940.

The photos come from the NYC Municipal Archives, which digitized and publicly released the collection in 2018. The city had originally photographed virtually every building in all five boroughs for property tax assessment purposes — producing a comprehensive street-level survey at a single moment in time, before urban renewal clearances, Robert Moses-era highway construction, and postwar apartment development remade large stretches of every borough.

Boilen, who has worked at Stripe and Squarespace and is based in New York, built the interactive map as a personal project. He described it on his own site as placing the Municipal Archives photos "on a map, building a street view of 1940s New York City." The GitHub repository for 1940s.nyc shows active commits as recently as this week; the tool is free and requires no account.

For anyone tracking a particular block's history — a community board member, a local researcher, a tenant trying to understand what occupied a parcel before a current owner — the 1939-1940 survey photos are among the earliest comprehensive street-level images on record across all five boroughs. Pin any address in a neighborhood that changed substantially after 1945, and the tax photo is often the city's own record of what was there first.