Jordan Salama, a 2019 Princeton University graduate and journalist, comes by his travel instincts honestly. His great-great-great-grandfather led a thousand camels along the Silk Road to trade goods in Iraq, Syria and Iran; his great-grandfather, a Syrian Jewish immigrant to Argentina, rode on horseback through the Andes as an itinerant salesman; and his father became a physician in Buenos Aires before migrating to New York City. Their stories, passed down through generations of a family that spoke “a spellbinding mix of English, Spanish, and Arabic,” have inspired Salama’s own explorations, including the one he describes in Every Day the River Changes: Four Weeks Down the Magdalena.

The Magdalena River, which is over 900 miles long and Colombia’s principal waterway, links the country’s diverse interior to the Caribbean Sea. It has long been a vital transportation mainstay, used and abused by the Colombian government, global industry, paramilitaries, guerillas, migrants, fishers and environmentalists alike. In 2016 the government signed a wobbly peace accord with the Revolutionary Armed Forces of Colombia and other guerilla armies, but the river’s future viability remains as unclear as its sediment-stacked waters. Salama is intent on learning everything he can, while he still can, about this endangered, legendary river that threads its way through Colombia’s history and people.

The Magdalena is central to many tales, both in fiction, as in the novels of Colombia’s revered author Gabriel García Márquez, and in the true stories Salama hears as he follows the river’s course from beginning to end. The people he meets and travels with share their experiences—from a jeweler selling silver filigree flowers, to a teacher delivering books to rural children via his two donkeys (Alfa and Beto), to the ill-fated anthropologist and activist Luis Manuel Salamanca, to Alvarito, the village kite master. They are, Salama writes, “ordinary people working tirelessly to preserve the natural/cultural treasures of a country much maligned by war,” and their fates are interwoven with the Magdalena.

Then there are the runaway hippopotamuses. Imported from Africa for the private zoo of notorious drug king Pablo Escobar, the hippos fled after Escobar’s murder in 1993 and now make the Magdalena and its tributaries their home. They have multiplied and spread over the past three decades, and they will pursue and attack any intruders. As Salama ventures deeper into Colombia, he can’t wait to find them.

By the time Salama ends his riveting journey, scrambling across the treacherous rocks where the Magdalena River meets the Caribbean Sea, he has already enticed readers to follow him on his next one.