The Desert View Tower is a historic roadside attraction located in In-Ko-Pah Gorge off Interstate 8 in Jacumba, California. It's not far from Ocotillo, which you mentioned in your previous question. The tower was built in the 1920s and has served as a landmark and rest stop for travelers in the desert.
The Boulder Park Mystery Caves and Desert View Tower make for a quirky and fun half-day trip for families who likes to explore and climb. This also makes a great roadside stop to stretch your legs if you are driving to or from Arizona, something we find ourselves doing fairly regularly. The carvings and tower are registered as an official California Historical Landmark.