Ed Schudel of Reston, Va., poses under a Tyrannosaurus rex on Saturday at the Smithsonian National Museum of Natural History. (Marvin Joseph/The Washington Post)

When the gigantic, jungle-patterned curtain was pulled away Saturday morning, letting a herd of dinosaur junkies into the refurbished fossil hall at the Smithsonian National Museum of Natural History, Colin Stancil was at the very front.

With a white, toothy dinosaur mask on his head and a pink T-shirt plastered with green dinosaurs on his body, the 17-year-old had the revved-up vibe of someone stranded in the desert with water in sight.

He learned to read at age 3 by memorizing dinosaur names. Can spell parasaurolophus without pausing. Is entering college in the fall to study paleontology. And after coming to the hall every month as a kid, and having that dino spigot shut off five long years ago, Stancil was ecstatic as the curtain was pulled away late morning.

“They’re such mysterious things to the human mind,” he said of the ancient creatures that are the centerpiece of the most popular exhibit in the most popular natural history museum in the world. “Finally!”

Stancil was part of a carnival that played out Saturday when the museum reopened its famous dinosaur exhibit after a five-year, $110 million renovation. It features a 66-million-year-old Tyrannosaurus rex skeleton dubbed “The Nation’s T. rex.” The new hall is now a brighter, interactive, human-centered presentation about something even more complex than fossils — the broader story of the Earth and the dinosaurs’ part in the history of its living things. Its new name — “David H. Koch Hall of Fossils — Deep Time” — incorporates a term coined by the naturalist-writer John McPhee.

There were drums, trumpets, a line across the museum and out the door, and a reminder by museum director Kirk Johnson to the crowd that the neighborhood used to be, 300 million years ago, a swamp. (“This was the original swamp,” Johnson said.)

The soaring rooms were quickly swarmed by people who haven’t had access to their dinosaurs since 2014, including the hardcore groupies — the ones with dinosaur clothing, tattoos, jewelry and facts they can rattle off like a baseball fan reciting pitching stats.

The woman with the dino dress and T. rex necklace that plunged into her cleavage. The 11-year-old who went to a preschool and kindergarten inside the museum. Someone whose nickname is “Mosasaurus.” The couple who got up at 7 a.m. and rode the Metro in their matching dino full-body PJs to have a date at the opening.

“When I was little, I got into it, and I never got out,” said Noah Beck, 17, who bought his girlfriend the identical lime and forest green hooded onesies for their exhibit-opening date. “When they closed, it was like: ‘Oh, no!’ I can’t believe I waited so long.”

Nearly 6 million people a year came to the space that was called the Hall of Extinct Monsters when it opened in 1911, even through its last remodel in the 1980s, which was primarily to craft a large space simply highlighting the specimens and artifacts. The new exhibition, with its starker, broader title, weaves humans in throughout, presenting dinosaurs as part of a multimillion-year story that unfolds in layers, of which we are one.

“I love how [the new exhibition] puts dinosaurs in the context of how the Earth has changed,” said Eugene Anderson of Silver Spring, there with his daughter, who is heading into sixth grade in the fall and was wearing a T-shirt that read, “Future paleontologist.”

“It shows the Earth as a surface,” he said, “and so much is happening underneath.”

Dinosaurs seem to be in action around the huge, open fossil hall. In one spot, the flapping wings of a huge, mechanical dino-bird buzzed. Two massive new exhibits showed dinosaurs in combat. Dino junkies felt free to let loose knowledge and trivia and insider dino jokes. (There is such a thing).

Overheard snippets:

“Stegasauruses have a chance of dying of blood loss.”

“There’s apparently a skull in there.”

“There are some that have long fingers like lemurs in Madagascar.”

And by midday, “Daddy, I’m tired and need water!”

Maria Credle brought her entire family, in matching dinosaur T-shirts, from Philadelphia to celebrate her 37th birthday.

“We’ve been waiting seven years for this,” the social worker said.

Her mother-in-law, Mary Credle, grinned. “We’re museum geeks.”

Walking into the expansive hall, the older woman was breathless. “They kept that from when I was 4 years old,” she said of a Triceratops fossil lying on its side beneath the open jaws of a T. rex. “They’re amazing. It’s the same bone that I’ve seen, but put in new.”

The last person to see the fossil hall in 2014 was then-4-year-old Skip Hommer, a Tysons boy who each year requested donations for his birthday — for the fossil hall — instead of gifts. A photo on his Dad’s phone shows the small boy at 11:03 p.m. on April 16, 2014 — the last visitor standing.

The first person into the hall Saturday was the 10-year-old rising fifth-grader, who has donated $2,500 so far. Walking in after the curtain raised, Hommer grinned: “I really love dinosaurs.”

Sarah Kaplan contributed to this report.