Over the past 75 years, just about every Navy warship has spent some time, in miniature form, in this pool in Bethesda.

That would be the David Taylor Model Basin, built so that naval engineers could perfect their designs in the nautical equivalent of a wind tunnel. Testing of miniature models is a surprisingly important element in shipbuilding, and defense contractors have tested every Navy ship in this half-mile long tunnel prior to construction.

The David Taylor Model Basin is one of the largest of these testing facilities in the world. Intricately controlled waves are generated at one end by a pneumatic wavemaker, and absorbed on the other by a damper. The wavemaker can precisely simulate a range of weather conditions to assess performance on the open seas or in a hurricane force storm. A sliding platform that bridges the oblong pool moves with the models and gathers data using high speed cameras and sensors.

The engineering of this system is remarkable. According to the American Society of Mechanical Engineers: “To meet requirements for uniformity … the rails on the basin walls upon which these carriages will run had to be far straighter and more level than the most perfect railroad track. In fact, to eliminate the effect of gravity on the motion of the towing carriage, the tracks are not straight in the usual sense, but follow the curvature of the earth.” The foundation of the building was laid directly on bedrock to ensure that the rails stay perfectly aligned.

The models themselves are also worth marveling at. This is the domain of the Navy Ship Model Program, a niche office that includes a Curator of Models and three conservationists. They produce and conserve models of all types: from utilitarian hull prototypes to intricately detailed museum pieces that can weigh thousands of pounds.

These decorative models are on display across the country. The best collection in D.C. is at the National Museum of the US Navy, where you can find a ten-foot long model of the USS Missouri that was built over 77,000 man hours at the cost of millions of dollars. 

An expanded version of this article originally appeared on DCist.com