"Iron Man" opened to phenomenal box office business this weekend in North America and elsewhere, kicking off Hollywood's summer season with the second biggest opening figure of all time for a non-sequel, preliminary figures released Sunday.

The Marvel comic book adaptation, distributed by Paramount, took in an estimated 100.8 million dollars in its opening weekend, easily exceeding expectations of an opening in the 70 to 80-million-dollar range for the three-day period, according to box office tracking firm Media By Numbers.

The film grossed 104.2 million dollars in U.S. and Canadian theaters since debuting Thursday night, making the second best opening of all time for a non-sequel after "Spider-Man," which earned 114.8 million dollars in its opening weekend six years ago.

"Iron Man," which stars Robert Downey Jr. as a millionaire arms trader with super powers, is the first release by Marvel Studios, which has begun financing its own productions after blockbusters like "Spider-Man," "X-Men" and "Fantastic Four" franchises were made by major studios.

Meanwhile, the film has grossed about 96.7 million dollars overseas in 57 countries and territories since it began opening Wednesday, putting its worldwide total at 201 million dollars.

"Iron Man's" opening marks a high-beat start of Hollywood's lucrative summer season, which runs from May through August and often accounts for some 40 percent of the annual box office receipts.

Sony's romantic comedy "Made of Honor," the only other new release this weekend, debuted in second place with 15.5 million dollars, while last week's box office leader "Baby Mama" fell to third with 10.33 million dollar.

Despite the huge opening of "Iron Man," the top-selling 12 movies this weekend took in 154.1 million dollars collectively, down 15 percent from the same weekend last year, when "Spider-Man 3" started the summer season with a record debut of 151.1 million dollars of all time.