The abandoned grounds and derelict greenhouses of this once-magnificent Edwardian estate are now a nature preserve open for exploration.

One kilometer of thick brass rod laid out before your eyes.

An illegally built ramshackle mansion tucked in the middle of Brooklyn is now being turned into condominiums.

A decommissioned military complex that's now a modern industrial park.

A crumbling hospital from the 1850s on Roosevelt Island.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

One of only two commuter aerial tramways in the United States.

A former seaside jewel built for the everyman is now simply a neglected art deco fortress.

This abandoned seaside fortress is now simply an imposing ruin being taken back by nature.