Historic Sites

United States Naval Observatory

The agency that discovered the moons of Mars and still sets the nation's clocks also happens to be where the Vice President sleeps.

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Active since 1830 — when it began as the Depot of Charts and Instruments — this Navy facility measured the speed of light, discovered the moons of Mars, and produced data for the first radio time signals. It moved from Foggy Bottom in 1893 to escape light pollution, making it one of the very few pre-20th century astronomical observatories still operating inside an urban area.

What to look for

Located in Northwest Washington D.C. at the northwestern end of Embassy Row. It is an active military facility — public access is not detailed in available sources, so confirm tour availability directly before visiting.

United States Naval Observatory is one of 37 sights worth the detour in Washington, all bundled offline in Voyage GO — download the Washington pack and it sits on your map with no signal, filling your travel passport the moment you walk past.

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