On a chilly January afternoon, Susannah Maidment stands on the shore of a London lake, staring down a pack of dinosaurs.

Maidment, a curator at the U.K.’s Natural History Museum, has come with me to tour Crystal Palace Park, which in 1854 included the world’s first public dinosaur showcase. The sculptures were a smash hit at their unveiling and sparked the dinomania that’s been with us ever since. More than a century before Steven Spielberg dazzled the world with Jurassic Park, the Crystal Palace dinosaurs drew two million visitors a year for three decades straight, and Charles Dickens name-dropped one in his novel Bleak House.

To grant us a detailed look at these 166-year-old monuments, Ellinor Michel and Sarah Jayne Slaughter, trustees with the nonprofit Friends of Crystal Palace Dinosaurs, guide us through a metal gate to the banks of the lake, where we don waders to make our crossing. I misjudge my first step and fall into the water, clambering onto the island’s shore, dripping wet and smelling of pond scum. “Welcome to Dinosaur Island!” Slaughter exclaims, grinning from ear to ear.