The tallest peak on earth, when measured from base to summit Mauna Kea is the tallest mountain on Earth. It is truly a breathtakingly massive site. While there are no dramatic rock faces or steep spires, the shear girth of the mountain is very impressive. What is also neat is how accessible the top of the mountain is. The summit is around 13.8K feet above sea level, and there is a visitors center that is around 10K above sea level. There are multiple telescopes at the summit (as seen in the photo's below). There is a fairly descent gravel road all the way to the top, with some pretty steep grades. When you get to the top it is very easy to feel the altitude. I came to the mountain thinking I lived at 6K ft above sea level so I would be just fine. While I was "Fine" I did also feel the affects of the altitude, as did those I was traveling with. Going from 0-13.8K above sea level in a day isn't a small task, so if you made the trek be prepared.
From a photography perspective taking pictures at the top was really neat. My time there was cut a bit short as the wind was bitterly cold and biting. I had come prepared with a parka, hat, gloved, multiple layers of clothes; but somehow that didn't seem to be enough. I guess sometimes no matter what you have you will still be cold; either that or my previous week in Hawaii had thinned my blood so bad that there was no hope of me staying warm.