ORLANDO, Fla. - Thousands of people waited in line for hours Friday to get into the Wizarding World of Harry Potter at Universal Orlando on its opening day, as Daniel Radcliffe and other stars from the movie greeted fans at the minipark.

Aerial photos of Universal Orlando showed thousands upon thousands of people in line. On Twitter and other forums, observers joked that the park had become "Harry Potter and the Endless Line."

Universal Orlando spokesman Tom Schroder said the park would not divulge attendance figures but he said 5,000 people were waiting to get in before the park even opened Friday morning.

The park was admitting guests to the 20-acre Wizarding World area in waves, so it did not appear overcrowded from the inside. But the line to enter the Wizarding World snaked all the way through Universal's Islands of Adventure park, where the Harry Potter area is located, to the Universal entrance at City Walk, according to Robert Niles, editor of ThemeParkInsider.com.

"It's absolutely jampacked," said Niles in a phone interview. "The entire Islands of Adventure theme park and City Walk are just one long queue to get into Harry Potter. The number of people here for this is clearly in the tens of thousands. These are passionate fans."

Schroder said "everyone who wants to experience The Wizarding World of Harry Potter will be able to do so."

The Wizarding World brings the popular Harry Potter books and movies to life with rides, shops and detailed reproductions of the fictitious village of Hogsmeade, the Hogwarts School of Witchcraft and Wizardry and the steam-belching Hogwarts Express train.

Radcliffe, who plays the boy wizard in the movie series, was joined at the opening by Warwick Davis (who plays Filius Flitwick), Bonnie Wright (Ginny Weasley), Matthew Lewis (Neville Longbottom), Tom Felton (Draco Malfoy), James and Oliver Phelps (Fred and George Weasley), Rupert Grint (Ron Weasley) and Michael Gambon (Albus Dumbledore).

"What Universal Orlando has done with Harry Potter is really, really fantastic," Radcliffe said at the opening ceremony. "We're all kind of very grateful that the next part of the Harry Potter legacy has been so well-done and so well-made."

The park's marquee ride, Harry Potter and the Forbidden Journey, is filled with special effects as it takes guests on a flight through Harry's life, including encounters with Dementors and a dragon, and projections of characters from the film like Dumbledore, headmaster of Hogwarts.

The park also has two roller coasters, Flight of the Hippogriff and Dragon Challenge, as well as themed stores like Honeydukes confectionary and Ollivander's Wand Shop.

"We have brought to life a cultural phenomenon that has captured the hearts and minds of millions of people around the world," said Bill Davis, president of Universal Orlando Resort.

The Orlando Sentinel reported that Universal received a vague bomb threat Thursday night, but that "appropriate precautions" were taken and it was being investigated.