The Smithsonian

Since 10 of the Smithsonian museums are located on the National Mall, you'll see them on most Segway, bus, bike, and walking tours of Washington DC, some of which include free time to enter the museums of your choosing. Many visitors get their bearings on a guided city tour and then head back to the Smithsonian Castle, home to the Smithsonian Visitors Center, to pick up free guides and maps before heading to a museum.

All of the museums are free, though be aware you'll need a timed entry pass for the National Museum of African American History and Culture (bookable online and offered with some Washington DC/Smithsonian tours; a small number of same-day walk-up passes are also available on weekdays).

• Cameras are allowed, but leave the selfie sticks and tripods at home, as they're prohibited.

• Avoid bringing large bags and packages, as they'll be subject to a lengthy search process. Lockers are available for small items at some museums.

• All museums are wheelchair accessible.

• You can grab a cup of coffee at the Smithsonian Visitor Center café.

• To avoid crowds when exploring a museum, start on the top floor and move toward the ground floor, rather than starting at the first level.

All of the museums are easily accessible via public transportation, with most on the National Mall and a few others in downtown DC locations.

The museums are open year-round, and each has its own hours. You can expect to have company no matter the season, though the busiest times tend to be weekends, holidays, and during the National Cherry Blossom Festival. To avoid the biggest crowds, start your visit early in the morning on weekends or later in the day on weekdays.

It's impossible to see everything, so do a little research before you go. Does the Hope Diamond at the National Museum of Natural History top your list? The flight simulators at the National Air and Space Museum?

Or perhaps you have to see the collections at the National Portrait Gallery, the Freer Gallery of Art, the National Museum of the American Indian, the National Museum of American History, the Smithsonian American Art Museum, or the Renwick Gallery. Each has something special, so choose what's most appealing to you.

No, you cannot do the Smithsonian in one day. As the world's largest museum and research complex, the Smithsonian encompasses 21 museums, as well as the National Zoo. Most of its museums are in Washington DC (two are in New York). Try picking the ones that interest you most.

It's hard to quantify how long it would take to explore the Smithsonian, as the institute encompasses 21 museums, as well as the National Zoo. If you dedicated one day to exploring each museum (in Washington DC, New York, and Virginia), visiting them all would require at least 22 days.

Many Smithsonian museums—including the Air and Space Museum, African American Museum, and National Zoo—are very popular and crowded on weekends, in the summer, and over school holidays. For a calmer experience, visit early in the day and on weekdays, and otherwise avoid peak times.

It depends on the museum. Some require free, pre-booked timed entry Smithsonian tickets or passes. Of its 21 museums (and the National Zoo), the only one of the institute's members that charges admission is Cooper Hewitt in New York City. All others are free.

Yes, the Smithsonian is worth it. As the world's largest museum and research complex, it is a peerless institution, and its free-entry policy makes it accessible to all. Depending on your interests—from art and history to culture, science, and beyond—you'll likely find several museums that are right for you.

The Smithsonian is a large institution with multiple branches, so plan ahead to visit the museums that interest you most. Upon arrival, you may be subject to a security screening and bag search; firearms and weapons are prohibited. Do bring your camera, as personal photography is permitted at the Smithsonian.