Iguanodon lived during the Cretaceous period of the Mesozoic era. Specifically, it lived between 126 and 125 million years ago, during the Barremian stage of the early Cretaceous.

The Iguanodon lived between 126 and 125 million years ago. That would be between approximately 126000000 BC and 125000000 BC. That was during the Barremian stage of the Cretaceous period. The Cretaceous period was the last period of the Mesozoic era.

The Iguanodon lived between 126 and 125 million years ago. This is during the Barremian stage of the early Cretaceous period. The Cretaceous was the third and final period of the Mesozoic era, or the so-called "Age of Reptiles."

If you mean "How long did the Iguanodon exist for?" the answer is that they lived for about a million years or so, between 126 and 125 million years ago.

If you mean "How long was the Iguanodon?" the answer is that Iguanodon grew to be 33 feet long as an adult, but especially large individuals were up to 43 feet long.

If you mean "What era did the Iguanodon live in?" they lived between 126 and 125 million years ago, during the Barremian stage of the early Cretaceous period. The Cretaceous period was the final period in the Mesozoic era.

If you mean "What area did the Iguanodon live in?" they lived in Europe. Much of Europe was flooded by shallow seas during that time, and what was left was divided into many islands.

The Cretaceous period, lasting from about 145 to 66 million years ago, was the last period of the Mesozoic era, known for the diversification of dinosaurs and the emergence of flowering plants. It ended with a mass extinction event that wiped out the dinosaurs, allowing mammals to thrive and evolve. The famous dinosaurs like T. rex and Triceratops lived during this period.