17. Fort Totten
The tunnel in the second to last episode of season two is actually Fort Totten, a military installation in Queens, and also tunnels inside Baley Seton Hospital on Staten Island. Daredevil fights through the ninjas of the Hand to get back his mentor Stick, and later in the episode it’s revealed that Elektra is actually the mythical Black Sky, the weapon the Hand has been looking for. Elektra doesn’t know about this until now as well, because Stick has been hiding this information from her.