The Frank Stella's are the best. They are all over the city and they always look amazing. Two of my favorites are the Saatchi and Saatchi lobby (pictured) and the Citi Corp building in Midtown.

Lunch there before a visit at the MET with a walk in Central Park

The graphic designer Rudolph de Harak created a three-story digital clock installed on the exterior of 200 Water Street. The clock consists of 72 square modules with numerals that light according to date, hour, minute and second.

The Ford Foundation Atrium houses a miniature tropical rainforest. Its glass walls create a temperate environment for the garden, while also creating a seamless flow of green space between the atrium and Tudor City Park to the east. The Ford Foundation Gallery shines a light on artwork that wrestles with difficult questions, calls out injustice, and points the way toward a more fair and just future. The atrium is open to the public Monday through Friday from 8 a.m. to 6 p.m. and Saturday from 11 a.m. to 6 p.m. when the gallery has an exhibition on view.

My favorite place on Bedford Avenue, this bookstore has both new and used titles. If you're patient and look close enough, you can usually find a book that's worth more than they're asking. Not to mention their stellar selection of magazine titles. Good for design, art, photography, sociology, fiction, and everything in between.