I highly recommend Henri Cartier-Bresson: The Modern Century, an exhibition at New York’s Museum of Modern Art (MoMA) from April 11 through June 28, 2010. This show was made for photographers.
Before entering the exhibition, one sees that HCB was quite a traveller: maps at the exhibition’s 6th floor entrance trace his routes during various trips over the years. Inside, there is a large body of work, including many well known photographs and many that are unfamiliar — about 300 photographs in all. There are so many well-observed moments and delightful compositions. It is well-worth seeing the photographs that have influenced several generations of photographers.
The related book by Peter Galassi looks superb: Henri Cartier-Bresson: The Modern Century.
There is a good preview of the exhibition at this link on MoMA’s web site. And this web site offers a look at many photographs by HCB: https://www.artsy.net/artist/henri-cartier-bresson (— added 8/14/2017).
If a big HCB exhibit isn’t enough for one day, MoMA has some other very interesting things happening now, including:
I did a little photography along the way:
One of the maps showing HCB’s travels
The atrium at MoMA
Performance artist Marina Abramović
Viewing an automobile designed by Pininfarina
People sitting in MoMA’s Sculpture Garden
A stairway at MoMA
Andrew Wyeth’s Christina’s World
A place to sit near the 2nd floor Cafe
The HCB exhibition advertised on 54th Street