The Triassic, from 251 to 200 million years ago, constituted the period in which the dinosaurs appeared. This hall shoes the biology of these fabulous reptiles reconstructed not only from their bones but also from their footprints or ichnites, gastroliths (stones swallowed by some dinosaurs to grind food in their stomachs), coprolites or fossilized dung, eggs and nests. Furthermore, it is intended for the spectator to be capable of differentiating a dinosaur from other reptiles.

The oldest, best known and largest dinosaurs of their times existing in Europe have been chosen as characteristic representatives of this period, the Plateosaurus.

Another part of the hall is destined to the deposits of Montral-Alcover, located in the Sierra de Prades (Tarragona).

Also, one of the walls of the perimeter ramp of the hall shows several portraits of distinguished researchers regarding the world of dinosaurs.