As of Friday morning, the five flags other than the United States flag representing France, Spain, Mexico, the Republic of Texas and the Confederacy are being left to the history books.
The park received criticism following last weekends violence in Charlottesville, Va., from TMZ, Fox News and others for flying the Confederate states flag.
As a result, Six Flags decided to take all but the U.S. flag down as of Friday morning.
Source
(For those outside the US, Six Flags is an amusement park with rollercoasters, that sort of thing)
The name "Six Flags" refers to the flags of the six different nations that have governed Texas: Spain, France, Mexico, the Republic of Texas, the United States, and the Confederate States of America.