WATCH: Digitally preserving part of African-American history
Throughout the first half of the 20th century, African-Americans began moving out of the South to cities in northern states like New York in search of a better life, a period known as the Great Migration.
It coincided with the proliferation of American car culture and eventually the interstate highway system.
But prior to the Civil Rights Act of 1964, traveling was complicated for African-Americans as segregation was still the law of the land. Hotels, motels, campgrounds and even some gas stations were off-limits for American black people, unless you knew which places were safe to stop and stay.
So, in 1936, a Harlem postman named Victor Green set out to create a travel guide for African-Americans, The Negro Motorists Green Book.
Inspired by similar tour guides aimed at American Jews looking for safe and welcoming places to stay, the Green Book offered locations of "tourists homes," hotels, restaurants and even national parks that could offer "Assured Protection for the Negro Traveler."
To help keep this crucial piece of American history from being lost to time, the New York Public Library is making 30 years of the travel guide digitally available for free through its website.