Rock formations along the Backbone Trail in Malibu Creek State Park. This segment of trail is part of the Malibu Creek Trail Challenge and Bulldog 25K and 50K.
The final quarter-mile of the infamous Bulldog climb can be seen along the right skyline. I'd just struggled up that a few minutes before. An elevation gain of 1700 ft. in 3.5 miles sounds not-so-hard sitting in front of a computer, but the climb has few breaks and is longer and steeper than those figures convey.
The Bulldog climb is part of the ~14.5 mile Bulldog Loop -- an excellent course that is popular among runners and mountain bikers. My Polar HRM says the elevation gain/loss on the loop is about 2700 ft., and a GPS trace from a Forerunner 205 in TOPO! says the gain/loss is about 3000 ft. In 2004 Sal Bautista ran the slightly shorter version of the loop done in the Malibu Creek Trail Challenge in under 1.5 hours! Here's a Google Earth image of a GPS trace of the Bulldog loop.