Although it looks like a soulless concrete flood-control channel today, the once-wild Santa Ana River is ancient. Over time it helped create Newport Bay, carved the bluffs below downtown Huntington Beach, and sometimes cut across Anaheim and met the sea as far north as Alamitos Bay. But as Orange County became more populous—and a 1938 flood killed nearly 60 people—the battle to tame the river began. From reinforced berms, to Prado Dam, to concrete channels, we’ve done a lot to protect ourselves from the river’s wrath. But it never pays to get cocky with Mother Nature.