The Devil's Den is a prehistoric "solution sinkhole" and underground spring located near Williston, Florida. It is a stunning geological formation known as a karst window, where the roof of a subterranean cavern collapsed to expose a pool of crystal-clear, geothermally warmed water that stays a constant 72°F (22°C) year-round. The name originates from early settlers who saw steam rising from the cave's chimney-like opening on cold mornings, resembling "smoke from hell." In 2026, it operates as a world-class scuba diving and snorkeling facility. The cavern is shaped like an inverted mushroom, measuring about 100 feet across at the surface and expanding to 200 feet underwater. It is also a site of immense paleontological significance; excavations have uncovered fossils of extinct Pleistocene animals, including mastodons, saber-toothed cats, and dire wolves, alongside human remains dating back roughly 10,000 to 75,000 years. Access is strictly for snorkelers and divers; casual "swimming" without gear is not permitted.
To truly appreciate the diverse landscapes of both the North and South Islands in 2026, a minimum of 14 to 21 days is highly recommended. New Zealand is deceptively large; while the landmass is similar to the UK or Japan, the winding, two-lane roads and mountainous terrain make travel times much longer than they appear on a map. A 14-day itinerary typically allows for 5 days on the North Island (Auckland, Rotorua, and Hobbiton) and 9 days on the South Island (Queenstown, Milford Sound, and Tekapo). If you have only 7 to 10 days, it is a "pro-traveler" rule to stick to just one island to avoid spending your entire vacation in transit. For those planning a full circumnavigation including hidden gems like the Coromandel Peninsula or the Catlins, a 30-day "slow travel" pace is ideal to account for the frequent weather changes that can occasionally delay outdoor activities and scenic flights.