The Torrey Pines Reserve is just a short drive north of downtown San Diego, CA. This 2,000-acre reserve is a fine example of what southern CA looked like before the coastlines were developed.
The trails are mostly easy hikes. Either you can hike a longer loop around the entire reserve, or take a short walk from the parking lot near the nature center to the edge of high bluffs overlooking the ocean. You can see a great view of La Jolla from here. Sometimes you can see hang-gliders drift past and other times, you can see pods of dolphins swimming along the coastline. There are also many kinds of birds and there is a nest of peregrine falcons in the cliffs.
My husband and I hike here often. If you want to make your hike more difficult, you can start at the parking lot down near the entrance and hike up the large hill into the reserve. This is a beautiful place to get away and experience natural California coastline without having to drive too far!
Safety tip: If you hang out at the base of the cliffs by the ocean, please heed the "Keep Away From Cliff" signs. These are sandstone cliffs and they do crumble.