Obelisks are phallic (penis) symbols related to the Egyptian Sun god, Ra.
The 4 sides of the Washington Monument are aligned with the cardinal directions (i.e., east, west, north, and south). At the ground level each side of the monument measures 55.5 feet long, which is equal to 666 inches. The height of the obelisk is 555.5 feet, which is equal to 6,666 inches.