Puʻu o Lokuana

High points like this red cinder cone make great lookouts no matter whether you're Kamehameha keeping an eye out for rival chief Keoua in the 1780s, Captain Brown watching lava consume your house in 1868, or the US Army scanning for Japanese ships and planes using secret new RADAR technology in 1942. In the last case, the looking-out happened below ground where 'scope dopes' analyzed blips transmitted from the tower above to monitoring rooms carved into the cone's core.

The concrete blocks of the radar tower were set aside as the ranch mined the top 100ft of cinder to pave area roads. If you don't want to do the whole trail, you can join the trail across the street from the landing strip and get to the crater in a few hundred feet (cheater!).