Complex sentence: Every mid August, the carnival to celebrate the formerly enslaved African Gaspar Yanga, for defeating the Spanish, and creating what is advertised as the 1st free city in the Americas in 1699.
Split into simpler sentences: Every mid August, the carnival to celebrate the formerly enslaved African Gaspar Yanga take place. The celebration is to commemorate the defeating of the Spanish, and creating what is advertised as the 1st free city in the Americas in 1699.