The guest lecturer on board is excellent—a wealth of information on Lewis and Clark and all things related to the river. He even dresses each day in authentic costumes.
Most interesting is the epic story of the salmon and how they has been affected by alteration of the river. Obviously, the dams impact their ability to go upstream to spawn and then also for the young get to the ocean. But they are being successfully helped.
At The Dalles is the Maryhill Museum of Art. It has eclectic collections, including many Rodins. It is in a house built by Sam Hill. He also constructed a complete replica of Stonehenge as a memorial to the fallen of WWI. It is constructed of cement.
By the way, before we left on the boat, we found the very first geocache ever placed in 2000 There is a plaque to commemorate it.