The blue of Crater Lake is indescribable and unforgettable. It's a color you've never seen before. Cameras can't capture it, and memories don't prepare you to see it again... they don't truly capture it, either. In terms of the physics of the situation, I understand how Rayleigh scattering in exceptionally pure and deep water returns this optically distilled color, but in terms of my emotional response, I'm never prepared to see this blue.. It's always a surprise.
The closer of the two re-entrants beyond Llao Rock in the above photo is named Steel Bay; the farther is Cleetwood Cove. The latter is the only sanctioned place for visitors to actually reach the lake itself, via a 1.1-mile trail, with about a 650 foot elevation change. It's a hike I've never done, and right on the edge of what's currently possible for me. Note to young geologists: take every opportunity that arises to do it while you still can. There will come a time when you can't.
Llao Rock from Merriam Point isn't as pretty as it is from more of a distance, looking more orthogonally. Nevertheless, with a 1200 foot sheer drop, this dacite flow is an impressive cliff. More information on this feature can be seen here.
The benchmark at Merriam Point lists an elevation of 7317 feet. The question of whether Mount Mazama was a unitary peak, or a high platform with several peaks- Three Sisters has been mentioned as a possible analogy- is unresolved. Frankly, I have no idea how one would even go about answering that question. But it is intriguing, looking at this little brass plaque, to wonder, "How much higher did the mountain go from here?"
Kerr (pronounced "car") Notch is a terrific example of a beheaded glacial valley; the classic "U" shape is clearly visible. I don't know whether this valley was occupied by ice when the great cataclysm occurred, though it seems doubtful to me that it was. This would have been on a SSE-facing slope, well after the end of the ice ages, so it seems most likely to me that the feature was carved during the Pleistocene, and was simply a stream at the time of the great eruption. This spot is also the head of Sand Creek. Farther down the valley, ignimbrite deposits have been carved into "The Pinnacles," which was my selection for "sexy geology" a couple years ago. (The associated Wedge is here.)
Mount Scott is the highest point on the Crater Lake rim. I've never made the hike, but there's a two-and-a-half mile trail, with about 1500 feet elevation gain, to the top of this peak. The view from there looks incredible.