Recently (in 2007) he had a 40 year retrospective of his work at MoMA which pretty impressive for someone to have while they're alive. MoMA produced a few videos to accompany this exhibition called Serra Sculpture: Forty Years. This one is my favorite, it's him talking about the sculpture designed specifically for a space. It really is fantastic. It gives you a feeling for just how much work and innovation is put into his pieces, but also how well thought out things are. One of the things I dislike most is when people think a piece of art isn't good becaues it looks simple or easy. We can often fall into this with Serra's work because of its simplicity, but this video proves it is anything but.
Here's Richard Serra in front of one of the same type of sculptures, if I had to guess I'd say it was at the Bilbao Guggenheim. For the opening of that museum he was commissioned to create sculptures to fill their largest gallery.
Here is an aerial view of the same gallery. Beautiful.