One of the things the backcountry of San Diego is not known for is an abundance of lakes due to the arid climate of Southern California. But, just because such spots are not common, does not mean they do not exist, as the Water of the Woods, Sheperd’s Pond, and some other spots demonstrate. The easiest backcountry lake to hike to in San Diego is Upper Otay Lake; which is also somewhat of a secret location as it is overshadowed by its larger brother, Lower Otay Lake. Both of these man-made lakes are found in the Otay Valley, and were constructed in 1897 (and rebuilt in 1918), and 1959 respectively. While Lower Otay Lake is extremely visible as it occupies most of the Otay Valley, and is accessible by car at numerous locations, Upper Otay Lake is hidden in plain sight behind the Upper Otay Reservoir, and is accessible by a short hike.
Sunny Jim Cave
La Jolla, California is a sunny spot with sandy beaches. It is a spot that is well-known for a small cove (La Jolla Cove) where snorkeling, swimming, and scuba diving is popular. It is a location where locals and visitors can view sea lions and seals easily; and it is also a location that has an unobtrusive building with a secret tunnel that leads to a sea cave that is better suited for pirates, smugglers, and every adventure imaginable. For the last one hundred and ten years, this sea cave – the Sunny Jim cave – has been one of San Diego’s best long term microadventures, and is a location with a unique history.
La Mesa Secret Stairs
One of the best things about living in San Diego is the enormous amount of diversity - biodiversity - and topographical diversity that the area provides. From the beach to the plateaus, foothills, and eventually the mountains, there are plenty of spots that have either been eroded away to form something unique, or altered by man to construct a unique spot. One of the quintessential man-made "secret" spots is the "secret stairway" of La Mesa.
Old Mission Dam
While San Diego is a young city in terms of history, it has a number of hidden historic gems. Many of these locations are clustered near the current city center (such as the Whaley House), but one of the spots, the Old Mission Dam, is located in the middle of San Diego's largest municipal park, Mission Trails. The Old Mission Dam is a historic structure for a number of reasons, but first and foremost, it is the oldest colonial engineering project on the Pacific Coast.
Desert View Tower
While there are many interesting things to see between San Diego and El Centro, the most visible is the Desert View Tower. Constructed in 1922 by Bert Vaughn as a roadside attraction, the Tower is also located near the old Mountain Springs Station, which was used from 1862-1870 as a stopping point for wagons hauling items from Yuma to San Diego.
Kwaaymii Point
One of the more obscure and strange hiking destinations in San Diego is located on the Eastern border of the county, and sits right on the border of the Anza-Borrego State Park and the Cleveland National Forest. In addition to being one of the strangest hiking destinations, the spot has some of the best views in the county as it is located on the edge of the Laguna Mountains.