When they hear the name Auguste Rodin, the first thing most people will remember (aside from him being one of the most awesome artists ever) is The Thinker: A gigantic man hunched over a rock, utterly focused on his philosophical pondering. The detailed design and musculature show off Michelangelo’s influence, but only Rodin could’ve captured that kind of expressiveness. In terms of fame in popular culture, The Thinker comparable to the Mona Lisa. What most people don’t know is that it started as part of a much bigger project (and serious contender for my all-time favorite sculpture I’ve personally seen) called The Gates of Hell. Rodin eventually decided to make this a separate work, resulting in a modern sculpting legacy. There are now over 30 Thinkers in existence, spanning museums and universities around the planet. This one is the centerpiece of the court at the Legion of Honor in San Francisco. Larger version is viewable here.
There are plenty of sea lions at Pier 39, but these are the only ones that stand still. Edit: Upon a further Google searching, this statue is officially known as the Guardians of the Gate.