I spent a couple days near the mouth of the Columbia River learning about the travels of Lewis and Clark. Luckily, our expedition was blessed with bright sunshine, not the “rain as usual” that plagued those weary travelers two centuries ago.
The interpretive center at Cape Disappointment has, in addition to an extensive exhibit on the Lewis and Clark expedition, an old fresnel lens from the lighthouse there. (You can even see cracks and chips in the glass from all the years it stood exposed to the elements.)
For someone like me who likes to play with light, a fresnel lens is a veritable playground.