National Building Museum

The National Building Museum is the best indoor room in Washington that most visitors never see. It occupies the old Pension Building, completed in the 1880s to house the federal office that paid pensions to Union veterans and their families, designed by Montgomery Meigs, the army engineer who also helped shape Arlington National Cemetery. Outside, a long terra-cotta frieze runs around the whole building showing Civil War soldiers, sailors and wagons in procession. Inside is the surprise: the Great Hall, a vast open courtyard rising the full height of the building, lined with arcades and dominated by eight colossal Corinthian columns, among the largest interior columns in the world. It has hosted presidential inaugural balls since the late nineteenth century, and simply standing in it is worth the stop. The Great Hall and the museum shop are always free. The exhibitions, which cost a modest ticket, explore architecture, design, engineering and cities, and the family hit is Brick City, a LEGO cityscape that is closed for a refresh in late fall and reopens in late November; a temporary LEGO building activation fills the gap through the third week of November. Summer often brings a large installation to the Great Hall, and free historic building tours run when docents are available. The honest notes: the museum is open Thursday through Monday only, closed Tuesdays and Wednesdays, so plan the week accordingly, and the exhibitions are smaller than the room suggests. Fit: families with LEGO fans, architecture lovers, first-timers wandering Penn Quarter, and anyone looking for a dramatic free room to rest in between Ford's Theatre and the Capitol.

The building is the main exhibit. Meigs designed the Pension Building as a fireproof, well-lit, well-ventilated office for hundreds of clerks, using clerestory windows and open galleries to keep air moving in the days before air conditioning, and he built it of millions of bricks because brick was cheap, sturdy and quick. The giant columns are made of brick too, finished to look like marble. The Pension Bureau moved out in the 1920s, the building served other government offices, and Congress created the museum in 1980 to celebrate the American building arts. The frieze outside, by sculptor Caspar Buberl, rewards a full walk around the block, and the Great Hall's fountain and upper arcades give the best views down into the space. Look for the small details too: the window frames and stair rails were designed with the same practical intelligence, and the building was one of the first in the city to be planned around natural ventilation. Architecture students come here to see how a nineteenth-century office solved problems modern buildings still face, and the museum's exhibits keep that theme going with displays on housing, climate and the future of cities.

Visit craft: start by walking into the Great Hall and up to the upper levels for the overhead view. If you are bringing children, buy exhibition tickets for the LEGO and design galleries, which are hands-on and perfect for a rainy afternoon; same-day tickets are sold at the visitor center, but booking ahead is suggested. Ask at the desk about free building tours, which depend on docent availability. Check what is in the Great Hall before you go, since inaugural balls, galas and summer installations change the space.

Practicals: 401 F Street NW, directly across from the Judiciary Square Metro (Red Line) and two blocks from Gallery Place. Free admission programs are available for SNAP EBT cardholders. Combine it with Ford's Theatre, the National Portrait Gallery and Chinatown in a compact Penn Quarter afternoon, then walk down to the Capitol.