For a memorable history lesson, check out the crumbling ruins of Contaduria Ruins and picture how it would have looked in its prime.
You'll have sightseeing choices galore when in San Blas. Contaduria Ruins is a good place to kick off here, but there are loads of other interesting attractions to check out. Matanchen Bay Beach, Las Islitas Beach, and San Blas River are close to the once-important structure and will round out your day nicely.