Explorers Hall rotates exhibits related to exploration, adventure, and earth sciences, using interactive programs and artifacts. A recent exhibit included Sir Edmund Hillary: Everest and Beyond, celebrating the 50th anniversary of Hillary's ascent of Mount Everest. Most exhibits consume about an hour of touring time. If you are a fan of National Public Radio's Diane Rehm talk show, you may want to join the audience for the Friday morning live broadcast of the show produced in this building, in the Grosvenor Auditorium. Rehm's 10am to noon, Friday show always uses the first hour to host a panel of journalists discussing and analyzing the top news stories; and the second hour to feature conversations with a scientist, author, or newsmaker. Call tel. 202/857-7700 or e-mail drshow@ngs.org, by 4:30pm of the preceding day to reserve a seat in the audience. Admission is free, but you must have a reservation and bring a photo ID. When you make your reservation, you will be asked to indicate the date of the show you'd like to attend, the name of everyone in your party, your daytime phone number, and whether you intend to stay for the first, second, or entire two hours.