ultrafacts: Surrounding the base of the monument is a terrazzo floor embedded with a “star map
ultrafacts: Surrounding the base of the monument is a terrazzo floor embedded with a “star map”. The map depicts the Northern Hemisphere sky at the moment of President Roosevelt’s dedication of the dam. This is intended to help future astronomers, if necessary, calculate the exact date of dedication. (Fact Source) Follow Ultrafacts for more facts -- source link