It's a nice museum. I haven't gone through the whole thing, but it wouldn't take up too much time. (my mgr at work made a bunch of us go so we could take a picture in the jail cell). It's in it's own building on a little square off of Water Street. The building looks like a police precinct and has the old lights and a few old cruisers parked outside. The 9/11 exhibit is in two rooms and has a lot of things that were damaged and pulled from the rubble. There are video screens stacked in the shape of the towers showing different footage from the whole thing. It's tough and real. I have not been to the new memorial that's opened (probably never will). I'm sure that is more extensive, but the museum has other things too so if you like old cop stuff, it's fun. They have a whole room with old gangster things, like weapons in violin cases. Really old and genuine. You can take pictures in the jail cell and you can also take a mugshot. There were two floors that we didn't go to, but here's the website.

http://www.nycpolicemuseum.org/