Complex sentence: On the courthouse square is an original wooden Confederate flagpole, erected in 1861; the monument is 100 feet tall and is believed to be the only original Confederate flagpole still standing.
Split into simpler sentences: On the courthouse square is an original wooden Confederate flagpole, erected in 1861 and still stands today. This monument is 100 feet tall and is believed to be the only original Confederate flagpole still standing.