At the local Foodland market, take Pupukea Road up the hill to reach Puu o Mahuka Heiau, the largest preserved Hawaiian place of worship on Oahu.  It is told that human sacrifices once took place here on this lonely bluff above Waimea Bay. During your visit to the temple, you'll notice that there aren't many visitors plus there is an eerie silence surrounding the historic site.  Spooky!  For a more down-to-earth experience, check out Waimea Valley Audubon Center where visitors take a self-guided nature walk to visit 40-foot Waimea Falls.