Which was the largest dinosaur?

The largest dinosaurs were titanosaurs, huge plant-eating sauropods with long necks and tails that lived during the Cretaceous period. Argentinosaurus and Patagotitan, both found in Patagonia in Argentina, are among the strongest contenders, with estimated lengths of up to about 35 metres. Weight estimates vary widely, from around 50 to more than 70 tonnes, because scientists usually have only partial skeletons to work from. Patagotitan was formally described in 2017 from the remains of several individuals, making it one of the best-known giant sauropods. Even these giants were probably lighter than the biggest blue whales, which can exceed 150 tonnes.