Hello,

I'm going to New York for 4 days and would like to have a look at the best buildings and have nice vegetarian food!
Any tips would be great.

You won't have a hard time at all finding vegetarian food in NYC. Most restaurants have options, especially Asian and Indian joints.

This may be of use

http://www.happycow.net/north_america/usa/new_york/new_york_city/index.html

I'm not a veggie and I don't seek it out, but I can attest to the Organic Grill, on 1st Avenue at 7th Street.

A great website for restaurant recommendations is chowhound.com I don't know anything about New York...maybe someday!