Washington, D.C. Must-Dos

Paddleboat Rides at the Tidal Basin

"One of the best ways to see the architecture; get in touch with the Potomac, which is so central to the city."—Gabriel Einsohn, Smithsonian's Hirshhorn Museum. Views of the Jefferson Memorial and nearby monuments and cherry trees. One passenger must be 16 years; 10 a.m. to 6 p.m., last boat leaves at 5 p.m.; fee. 1501 Maine Ave., SW: tel. +1 202 479 2426. www.tidalbasinpeddleboats.com

International Spy Museum

"Operation Spy combines videos, themed environments, and hands-on challenges; people can try their hand at being an actual spy."—Colleen Clark, co-author, Night Day D.C. The country's only museum dedicated to the art of subterfuge and spycraft; see everything from James Bond's Aston Martin to storage devices for cyanide. Fee; timed tickets. 800 F St., NW; tel. +1 202 393 7798. www.spymuseum.org

U.S. Holocaust Memorial

"The same powerful effect as a visit to the concentration camps in Europe: Stark images and silenced voices will haunt you."—Andrea Sachs, travel staff writer, Washington Post. Photographs, memorabilia, and interactive elements assist in telling the terrible story of the death of millions of Jews during WWII. 100 Raoul Wallenberg Place, SW; tel. +1 202 488 0400. www.ushmm.org

Hotel Washington's rooftop

"A must-see nighttime view of the Mall and the White House."—Scott Elder, columnist, Washington Post Sunday Source. Stunning views of the National Mall from up high; open-air terrace with Southern patio furnishings; full bar and light meals. 15th Street and Pennsylvania Avenue, NW; tel. +1 202 638 5900. www.hotelwashington.com

Washington National Cathedral

"Meticulous work of master stonecarvers."—John Thompson, author, National Geographic's Washington, D.C. Tea and specialty tours Tuesdays and Wednesdays; soaring arches, marble floors, and gargoyles are highlights; President Woodrow Wilson's burial place; regular religious services. Massachusetts and Wisconsin Avenues, NW; tel. +1 202 537 6200. www.cathedral.org

National Mall

"Looks best at night, when the lights flicker on. The most stunning view is from the Lincoln Memorial steps."—Andrea Sachs. Includes presidential monuments, war memorials, the National Gallery of Art, the Capitol, the White House, and most Smithsonian museums. Most worthy of a good long look: Hirshhorn Museum and Sculpture Garden, Air and Space Museum, and Vietnam Veterans Memorial. www.smithsonian.org or www.nps.gov/nama

Ford's Theatre/Petersen House

"National park rangers lend dignity and chills to an American tragedy."—John Thompson. The Petersen house is across 10th St., where Lincoln died, open from 9 a.m.-5 p.m. daily; tours are free of charge. 511 10th St., NW; tel. +1 202 638 2941. www.fordstheatre.org

Library of Congress

"Original Maltese Falcon and Ken & Barbie at Madison building copyright exhibit."—Eve Zibart, author, The Unofficial Guide to Washington, D.C. Thomas Jefferson said that there "is no subject to which a Member of Congress may not have occasion to refer," and so the nation's library houses two copies of every book printed in the U.S.; building's interior features sculptures, frescoes, and tilework; extensive print and photograph collection; free docent-led tours. 101 Independence Ave., SE; tel. +1 202 707 5000. www.loc.gov

Arlington National Cemetery

"To cover more ground—the cemetery is 200 acres—hop on a Tourmobile bus, which stops at the main sights"—Andrea Sachs. Tomb of the unknown soldier; more than 100 graveside services each week; JFK gravesite eternal flame; Arlington House; near the Iwo Jima Memorial; final resting sites of astronauts, explorers, Presidents, and military personnel. Arlington, VA; tel. +1 703 607 8000. www.arlingtoncemetery.org

National Archives Houses

This houses original copies of the Declaration of Independence and U.S. Constitution (on permanent display), as well as hundreds of thousands of other lesser-known historical documents; a rotating exhibit program begun in 2005 opens the vaults on previously unviewed artifacts, papers, and letters. 700 Pennsylvania Ave., NW. www.archives.gov

National Zoo

"The new Asia Trail has sloth bears, leopards, and fishing cats in addition to the baby giant panda Tai Shan, who is a must-see."—Robert Rouse, D.C. Chamber of Commerce. Open 6 a.m.-8 p.m. spring and summer; 6 a.m.-6 p.m. fall and winter; buildings close two hours prior; no admission fee. 3001 Connecticut Ave., NW. www.nationalzoo.si.edu

Pentagon

Headquarters of the U.S. military. No public access outside of group tours, which must be requested at least two weeks in advance through U.S. state representative or foreign embassy. Memorial to 9/11 tragedy (construction ongoing on-site). Army Navy Drive & Fern St., Arlington, VA. www.pentagontours.osd.mil/tours