Complex sentence: This is one of three major surviving mounds in the Florida Panhandle from the Fort Walton Culture (1100 CE-1550 CE), a complex, hierarchical society that planned and constructed elaborate earthwork mounds as expression of its religious and political system.
Split into simpler sentences: This is one of three major surviving mounds in the Florida Panhandle from the Fort Walton Culture (1100 CE-1550 CE). This complex, hierarchical society planned and constructed massive earthwork mounds as expression of its religious and political system.