Written By: Eliza Berman

The Jurassic Park franchise grossed more than $2 billion at the box office over the span of three movies and eight years, with the original film ranking in the top 20 American box-office performances of all time. On Friday, the franchise roars again with Jurassic World, a fourth installment that imagines how things might turn out if a dinosaur theme park attempted to attract visitors by creating a genetically modified hybrid dinosaur. (By all appearances, the answer is “not well.”)

In 2015, we need genetic mutants and modern technology to amp up the drama. But in 1939, there was plenty of drama in the sheer possibility of seeing dinosaur fossils in a museum. That year, New York City’s American Museum of Natural History debuted the largest fossil exhibit in the world, consisting of 200 specimens covering a time period of 200 million years.

Much of the collection came thanks to the paleontologist Barnum Brown, who had been excavating fossils since the 1890s. Among Brown’s treasures were a 66-ft. brontosaurus discovered in Wyoming and a nodosaurus, “resembling a huge horned toad,” originally found in 10,000 pieces near Billings, Mont.

Decidedly absent from the momentous exhibition? Indominus rex, Jurassic World’s violent hybrid of four real-life dinosaur species. Let’s hope that one remains a figment of Hollywood’s imagination.

Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter @lizabethronk.

The Trachodon was most common of dinosaurs. Back of the bill it had 2,500 teeth which, like the bullets in a machine gun, replaced one another as enamel wore off.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

Tyrannosaurus was the largest of flesh-eaters, has a skull which weighs 1,000 lb. Though it had tremendous hind legs, its front legs were no larger than a man's arm.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The 15-ft. step of an Iguanodont dinosaur was found in the roof of a coal mine at Cedaredge, Colo. The coal was mined away and the stone footprints were left.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

This new type of Iguanodont dinosaur had a duck-like bill with a few teeth. The tail, twice as long as the body, propelled the reptile through water.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

This 7-ft. Placodus existed 200,000,000 years ago,, it lived in the ocean, had well-developed flipper feet and at nothing but mollusks.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The American Museum of Natural History Dinosaur exhibit in New York, 1939.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The American Museum of Natural History Dinosaur exhibit in New York, 1939.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The American Museum of Natural History Dinosaur exhibit in New York, 1939.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The American Museum of Natural History Dinosaur exhibit in New York, 1939.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

This well-preserved Plateosaurus (oar lizard) was one of the earliest dinosaurs. It stood on its hind legs, had front legs which were terminated by powerful talons.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

The American Museum of Natural History Dinosaur exhibit in New York, 1939.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

Largest land tortoise that ever existed was found in India. This animal lived a million years ago, weighed 2,500 lb. in life and measured 7 ft. from tail to the head.

Dinosaurs 1939

Hansel Mieth The LIFE Picture Collection/Getty Images

More Like This

animals

When Maine Really Wanted Its Caribou Back

animals

Celebrities’ Best Friends

George H.W. Bush in 1971 animals

See Inside the Private Family Life of a Young George H.W. Bush

Troika race at Hippodrome, 1963. animals

The Mane Event: LIFE’s 25 Most Memorable Horses

Cats Blackie Brownie catching squirts of milk during milking at Arch Badertscher's dairy farm. 1954. animals

LIFE’s 25 Most Meow-Worthy Pictures of Cats

John Dominis African antelopes, 1969. animals

How John Dominis Photographed Wild Antelope Without a Telephoto Lens