In 1964, a white hotel manager named James Brock poured acid into a whites-only pool at the Monson Motor Lodge after Black activists jumped into the water during a "swim-in" protest.

—On June 18, 1964, motel manager James Brock poured muriatic acid into the swimming pool at the Monson Motor Lodge in St. Augustine, Florida, in an attempt to force out black swimmers who were protesting the hotel's whites-only policy. The incident was part of the St. Augustine Movement, a civil rights campaign that used nonviolent protests to challenge segregation in the city.

Brock's actions were met with outrage from the civil rights community, and they helped to galvanize support for the St. Augustine Movement. The incident also led to a national debate about racism and segregation.

The Monson Motor Lodge is no longer in operation, but the site of the pool where Brock poured the acid is now a memorial to the St. Augustine Movement. The memorial includes a plaque that tells the story of the incident and its significance.