X-Men Legends/Old Sewers, New York City

You start in the sewers under New York.

Outfall Tunnels
Nothing

Mainline Reservoir
Nothing

West Trunk Line
Shut down 1 pump 1 Danger Room disc (Focus 201)
 * Objectives
 * Collectibles

East Trunk Line
Shut down 1 pump 1 Comic Book 1 Sketch Book
 * Objectives
 * Collectibles

Morlock Haven
Go to the center of the room (the unnamed morlocks won't be of any help) to talk to the Morlock Healer (you'll unlock access to a new shop), then, talk to Marrow.

Mainline North
1 Sketch Book
 * Collectibles

Filtration Reservoir
1 Danger Room disc (Focus 202)
 * Collectibles

22nd St. Steamworks
1 Danger Room disc (check the left edge of the room before fighting the Boss, use someone with Flight)
 * Collectibles