Our member JNR13 has produced an overview of all the beautiful graphics of the buildings of the exploration era, and how the differ by culture. If you want to see a high resolution image of everything, then check out our thread here and join the discussion.
Firaxis also has released a new short about naval combat. It seems you will be able to use your ships not only to sail up the navigable rivers, but also to plunder and capture the settlements on the way. In the exploration age you can explore the seas a lot further than in antiquity, but your ships are prone to sinking from the rough sea. If you want to discuss these details with us, then check out this thread.