A New-york subway train submerged to 75% resting on a track in sea water with a man drinking cry baby and sunbathing on the roof. 

The pool of sea water contains aquatic life ranging from fishes to plants found near ocean shores. The train has doors open and has evidences of daily life within. The exhibit is first observed from the higher view point where one can see the train submerged. To fully experience the exhibit one enters the lower levels where you observer the submerged train revealing aquatic life thriving around it. Below one can view the exhibit from two locations, one a full glass view point and one windowed partial view point. Both locations display information regarding rising sea level. 

Full experience - enter gift shop / sucbagear shop - get fitted - progresses slowly to lower levels designed to look like new york apartments underwater.  enter the main display from the balcony of a submerged apartment. Exit in similar fashion (trainstation platform?)