Katz's Deli on Houston street is famous and it is landmark. You will be in Greewich village then (just called the village). Pastrami on rye with mustard and cole slaw is amazing. You get on line once you are in and order at the counter and bring to your table yourself. tip the guy making you sandwich. they usually put pieces of pastrami on the counter to munch while you are waiting him to make it.

Lots of museums.
Intrepid Sea, Air & Space Museum

Don't bring a gun!

So many guns, so little time!