LOS ANGELES – James Cameron's "Avatar" is on a course to sink "Titanic" at the box office.

No. 1 for the sixth-straight weekend with $36 million, the 20th Century Fox sci-fi spectacle lifted its domestic total to $552.8 million, according to studio estimates Sunday. "Avatar" raised its worldwide total to $1.841 billion. That's $2 million shy of first place behind Cameron's last movie, the 1997 shipwreck epic "Titanic," at $1.843 billion.

"It defies all superlatives," said Chris Aronson, head of distribution for Fox.

The studio said "Avatar" has hit $1.29 billion in international ticket sales, passing the $1.24 billion mark set by "Titanic." The saga set on the alien world of Pandora is also en route to overtake "Titanic" in domestic sales. After 37 days in theaters, "Avatar" soared past "The Dark Knight" on Saturday to become the second highest grossing film.

"We're witnessing box office history," said Paul Dergarabedian, box office analyst for Hollywood.com. "We're watching all of these big records fall, and there doesn't seem to be an end in sight. 'Avatar' is dominating at a time where it has no big summer blockbusters to compete with it. It's perfectly poised to keep breaking all these records."

"Avatar" is also positioned to win acclaim during awards season. While the computer-assisted performances didn't earn any honors at Saturday's Screen Actors Guild Awards, it captured the best drama and director trophies at last week's Golden Globes and is considered a likely best-picture front runner when Oscar nominations are announced Feb. 2.

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Screen Gems' apocalyptic thriller "Legion," featuring Paul Bettany as an Armageddon-fighting fallen angel, debuted behind "Avatar" at No. 2 with $18.2 million. Fox's family fantasy comedy "Tooth Fairy," starring Dwayne "The Rock" Johnson as a hockey player who spreads his wings as a magical deity, took flight in the No. 4 spot with $14.5 million.

Warner Bros. grabbed the No. 3 position with "The Book of Eli" at $17 million in its second week, despite three other films debuting in wide release this weekend. The post-apocalyptic action flick stars Denzel Washington as a traveling prophet who battles a villainous gang leader played by Gary Oldman while protecting the last known Bible.

The medical drama "Extraordinary Measures," the first film from new distributor CBS Films, opened with a disappointing $7 million in the No. 7 position. The film features Harrison Ford and Brendan Fraser as a doctor and businessman who collaborate to develop a drug that will treat a rare genetic disorder affecting children.

"It did well in middle America," said Steven Friedlander, head of distribution for CBS Films. "This is not a shoot-'em-up or fantasy film. It's the true story of people doing courageous things, and it's building good word of mouth. This is the kind of movie that plays well to a family friendly crowd who doesn't need to see the movie the weekend it opens."

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood.com. Final figures will be released Monday.

1. "Avatar," $36 million.

2. "Legion," $18.2 million.

2. "The Book of Eli," $17 million.

3. "Tooth Fairy," $14.5 million.

5. "The Lovely Bones," $8.8 million.

6. "Sherlock Holmes," $7.1 million.

7. "Extraordinary Measures," $7 million.

8. "Alvin and the Chipmunks: The Squeakquel," $6.5 million.

9. "It's Complicated," $6.2 million.

10. "The Spy Next Door," $4.8 million.