This secret bolt played a huge role in building New York City

In the early 19th century, John Randel Jr. set about planning what would become the gridded street plan of Manhattan. Randel spent ten years walking the entirety of the city, marking each future intersection with either a bolt or marble monument. Two hundred years later, one of the bolts still survives in a hidden spot in Central Park.

Produced by Matthew Stuart

Follow TI:On Facebook

Join the conversation about this story »