On one's first, second, and third visits to Washington, DC, one must concentrate on the memorials - Lincoln, Jefferson, Washington, Vietnam, the new WWII Memorial on the National Mall, and a little known treasure, the T. Roosevelt Memorial on an island of the same name on the Virginia side of the Potomac.

Don't even think about skipping the Smithsonian (although you could go there every day for years and not scratch the surface), the Capitol Building, White House, U.S. Mint; and FBI Headquarters. It is a fabulous city for visitors - it is even a fabulous city for those little people that get dragged along by their parents; they will appreciate the carrousel on the Mall, the huge locomotive in the Museum of Science and Industry and especially the insect room in the Museum of Natural History (tarantulas, scorpions, and Hissing Cockroaches - oh my.)

But if you live in DC or have visited there many times you may be a bit jaded by the tourist spots so we offer an offbeat suggestion; The National Builders Museum. This little known attraction is managed by the General Services Administration but largely funded by donations from the public and the building industry. Admission is free although a $5 donation is requested.

We visited primarily to see the Green House which opened in May of this year and will run through June 3, 2007. Green House is a small but fascinating exhibit featuring The Glide House and dozens of innovative green homebuilding products and practices. We will pay a lot more attention to the Green House over the next few weeks, but the National Building Museum is worth a few mentions of its own.

The NBM is easily accessible; located directly across from the Judiciary Square Metro Station (Red Line) and the building alone is worth the trip. It was originally constructed to house the U.S. Pension Bureau (at the time the government's largest funded agency accounting for almost one-third of the nation's budget) and was built between 1882 and 1887. A local acquaintance maintains that its real reason for being was to serve as a location for Presidential Inaugural Balls and there is some credence to his claim as this is the only place outside of the Oval Office where the Presidential Seal is permanently installed - in the rotunda floor. The first inaugural ball to be held there was Grover Cleveland's in 1885 and fifteen have been held there since including George W. Bush's in 2001.

The building's architect, General Montgomery C. Meigs, a West Point grad and lifelong Army engineer (he was also responsible for building the Washington aqueduct system and the Capitol dome) designed the building. Charged by Congress with constructing a fireproof and cost-efficient building he used over 15.5 million bricks, which were economical and easily available. At this time it was built the Pension Building was the largest brick structure in the world.

The Great Hall is reminiscent of the 15th Century Palazzo della Cancelleria in Rome and the exterior of the building is patterned on the Palazzo Farnese built in the 16th Century. The hall is cavernous - supported by huge columns at each end - reaching multiple stories toward the vaulted ceiling. Shorter columns support four stories of galleries that ring the hall and contain permanent exhibition space and classrooms for the museum's active program on building arts for DC school children.

Yet, in spite of the huge space, the museum feels comfortable and accessible. A small restaurant allows visitors and workers from the many nearby office buildings to buy sandwiches and salads and eat at tables in the great hall. A fountain and benches invite visitors to sit, rest, and enjoy the statutes representing the various building trades which are nestled in niches above the center bay of the Great Hall. The museum gift shop, which was named best museum shop in the city by The Washington Post, features a huge collection of books on building styles and design, green building, and architectural history. There are also innovative building tools, a large collection of products from recycled materials, and lots of inexpensive and creative children's toys.

Meigs did some interesting things in constructing his building. Congress did not appropriate enough money to allow elevators so he included elevator shafts so the machinery could be easily installed when funds were available. Lacking elevators he made the stairs deep with shallow risers which made the building accessible to disabled veterans who had to visit the building.

He wanted a healthy office building and designed a system that allowed fresh air to enter through the office windows while stale air could exit through clerestory windows above the fourth floor. He estimated that, under prime conditions, the total volume of air in the hall was replaced every two minutes. The building was originally lighted with gas which is notoriously dim, thus workers must have appreciated the natural light that permeates the space. Meigs also designed a system using a metal track with a basket suspended from a wheel or trolley on the track; this served to move documents from office to office while a dumbwaiter in one corner of the building moved paper work between floors.

The building fills an entire city block and is surrounded by a 1200-foot terra-cotta frieze of Civil War military figures. The 70 foot panels making up this long frieze are repeated in one of the internal stairways of the building.

The Pension Bureau moved out of the building in 1926 and by the 1960's it was considered obsolete and considered for demolition. A study, however, recommended that the building be restored for its present use and the museum officially opened in 1985.

The museum, on a blustery weekday, was crawling with kids, most appearing to be in the first to third grade age group. They were obviously having a great time. The fall programs for kids at the museum include a Festival of the Building Arts in which children work side-by-side with craftspeople to discover "the skills and secrets of the building arts and learn what it means to build green." Halloween featured a haunted house workshop in which kids were invited to build a miniature spook alley from wood and cardboard.

While the reason for our visit was the Green House, the several more or less permanent exhibits in the museum are worth noting. We will visit "Cityscapes Revealed" and "Washington, Symbol and City" before talking about Glide House and its products and innovations.