Rain that soaked into the ground thousands of years ago comes back up scalding, and five towns on four continents built their streets, their fortunes and their smell around it.
Pōhutu, in the Whakarewarewa valley at Te Puia, is the largest active geyser in the southern hemisphere and plays roughly once or twice an hour. At the 2023 census 46% of Rotorua's residents identified as Māori, well over double the national share.
Beppu discharges over 130,000 tonnes of thermal water a day from 2,909 vents — the largest output in Japan and the second largest in the world after Yellowstone.
Around 1,170,000 litres of 46°C water rise here every day from Britain's only hot springs. Bath is one of the rare places inscribed twice on the World Heritage list — for itself in 1987, and again in 2021 as one of the Great Spa Towns of Europe.
Around eighty mineral springs surface here, fifteen of them tapped for the drinking cure, and legend credits Charles IV's hunting party with finding the first around 1350. Becherovka has been distilled in the town since 1807.
The 47 springs deliver water at about 62°C that carbon dating puts at roughly 4,400 years old. The 1832 reservation became Hot Springs National Park in 1921, and Bill Clinton grew up in the town.
Think you'd have found them? Play today's expedition, or replay this one from the archive.