This 1929 gem of a mini-museum on Philly's Museum Row just might be my favorite in town.  "The Thinker" on his pedestal out front greets you to the largest collection of works by Pierre August Rodin (1840–1917) outside the Musée Rodin in Paris: 140 bronze, marble, and plaster sculptures, from recognizable icons such as "The Burghers of Calais" and "Balzac" to many smaller, more process-oriented bronze castings and plaster studies.  Just beyond "The Thinker," steps rise to a reproduction of a gate at the 17th century Château d'Issy, parts of which Rodin rescued from demolition in 1871 to create an architectural remix at his Meudon estate. 

This gate leads into a rigorously francophone space designed in 1926–29 by a pair of Frenchmen: A garden laid out by Jacques Gréber surrounding a temple-like building designed by Paul Cret, both reopened in late 2012 following a long restoration.

You don't even have to enter the museum proper—or pay admission—to see the massive, original bronze casting of the famous " Gates of Hell." It was cast for the museum's founder, Jules Mastbaum, from the plaster original on which Rodin labored for 37 years but never fully realized—though Rodin was inspired to turn some of its individual elements, such as "The Thinker" and "The Three Shades," into stand-alone works. Inside the museum, look for numerous Rodin busts and a number of (frequently erotic) marbles and bronzes, as well as original sketchbooks, letters, and books. There are also a few expert replicas of other Rodin works, such as Henri Gréber's "Copy of The Kiss."

Admission is only suggested; you can pay what you wish—and since this is, technically, a branch of the Philadelphia Museum of Art, the two-day ticket for that museum includes admission to this one. There's a free tour of the collections daily at 1:30pm.