Is it true that the Washington monument was built by the slaves?
Although the Washington monument itself was not directly built by slaves, it is possible that a number of the materials used in its construction were either mined, produced, or procured by slaves. Construction of the monument began in 1848 at a time when slavery was still legal within the United States although was not widely practiced in most of the Northern states.
Most states and benefactors sent ceremonial stones and plaques to be added to the monument throughout its construction and it is likely that a number of these stones were built by slaves, particularly those from the Southern States.
In short, technically the Washington monument was not entirely built by slaves, but it is also not possible to prove that slavery was not involved in its construction.