When visiting Congaree National Park, see if you can make it on the list for a ranger guided canoe tour. Check the website to see when registration opens and call as soon as you can—let me repeat, call as soon as registration opens! The groups fill up very quickly and you will likely have to call back multiple times to get through to the office. But it's worth it!
The tour lasts about two hours and the still black water reflects the cypress and tupelo trees perfectly. It's a great way to see more of the park than just hiking trails and the guides are helpful to point out areas of interest—like historic flood levels and wildlife.
The park also has a beautiful and wheelchair/stroller accessible elevated boardwalk that leads you on a short survey of the flora and fauna.