Turns out the Washington Monument is shorter than we thought

Using new international measurement standards and technology not available in the past, NOAA’s National Geodetic Survey has calculated the official architectural height of the Washington Monument to be 554 feet 7 11/32 inches [...].

Although the newly established architectural height differs from the historical height of 555 feet 5⅛ inches, neither the starting point nor the so-called “standard deviation” used for the original 1884 measurement is known [...]. — noaa.gov