National Academy of Sciences

Made up of approximately 2000 members, including almost 200 Nobel Prize winners, these are the folks the government hits up for scientific advice (whether the government listens to them or not is, as you may have guessed, entirely up to the government). Inside, the NAS displays its impressive permanent art collection and hosts temporary art exhibitions, lectures and films. Download the useful Visitors Guide from the website before heading here and be sure to bring photo ID.