This is Half Dome, one of Yosemite National park's most famous peaks. It elevation is 13,642 feet and the Hike is about 17 miles round trip which takes about 10-12 hours.

This picture only shows the last 500 ft of the hike. The rock surface is real smooth and requires wearing hiking boots. The only way up or down the top via steel cables, so you have to stop many times on the way to give space to people going in the other direction. There are no rocks, trees or bushes to break your fall if you happen to slip or fall from there and you'll end up at the bottom of the valley in record time :)

Going up!

Thats me in the circle :) .. I made the mistake of wearing running shoes to the hike and I started to slip right at the top where it gets really really steep. My friend took this picture with a 40x zoom.

A view of the Yosemite valley