As any native New Yorker will tell you – or won’t tell you – the city operates on its own clandestine “don’t ask, don’t tell” network. The good places stay hidden to keep them good, and the popular places are happily thrown to the masses. Even if we aren’t looking for the low-key, hidden, and incredible locations, there’s never been a moment in a New Yorker’s life where they haven’t singularly wondered, “What’s in there?”

Perhaps it’s on the way to work, on the stumble back from drinks or on a sunny stroll, but there are countless Manhattan locales that leave so much to the imagination of the passerby. It’s these quiet, unassuming places who’ve housed the city’s greatest minds, its most talented artists, its most incredible champions.

A Continuous Lean thought to expose these brick-and-mortar locations to the masses because sheer curiosity alone isn’t enough to buy you entry. The long, celebrated list includes: The Union Club – New York’s most historic club and America’s third oldest – established in 1836 on East 69th street, home to J.P Morgan, Dwight Eisenhower, Ulysses S. Grant; The Knickerbocker Club established in 1871 on East 62, frequented by J.P. Morgan; the Montauk Club established in 1889 on 25 Eighth Avenue in Brooklyn, frequented by Grover Cleveland, Herbert Hoover, JFK, and his brother, Robert; The Explorers Club established in 1904 on East 70th, home to Walter Cronkite, Elon Musk, Sir Edmund Hillary, and Neil Armstrong.

Check out the full list and more over at ACL.