"Iron Man 3" has passed another milestone: $1 billion in worldwide ticket sales as of Thursday.

After only two weeks in theaters, that places "Iron Man 3" at No. 16 on the list of highest-grossing films of all time, sandwiched between "The Dark Knight" ($1,004.6 billion) and "Harry Potter and the Sorcerer's Stone" ($974.8 million). It's the 16th film to earn $1 billion ever, the first of which was 1997's "Titanic." For star Robert Downey Jr., "Iron Man 3" is his second billion-dollar grosser after last year's "Marvel's The Avengers."

The movie also surpassed the $300 million mark domestically on Wednesday. It is currently the second highest-grossing superhero flick globally and is on tap to earn more than both of the previous "Iron Man" entries.

After its opening week in theaters, domestic ticket sales for "Iron Man 3" dropped off by 57.9 percent, according to Box Office Mojo. Even if it continues to dwindle at that same rate for the next three weeks, the movie's continued revenue would catapult it from its current spot at No. 43 on the highest-grossing domestic movies to No. 23, right behind "The Passion of the Christ."

It's unlikely "Iron Man 3" will steal the top spot at the box office again this weekend, as the hotly anticipated and equally expensive "Star Trek Into Darkness" soars into theaters. The movie opened Thursday to a cool $13.5 million --- slightly less than expected -- but Paramount reportedly expects it to hit at least $100 million at the close of its four-day run. ("Iron Man 3" nabbed $174.1 million by the end of its opening stint.)

Added competition for "Star Trek" and "Iron Man" will come from the second weekend of "The Great Gatsby" as well as the limited-release debuts of the Aaron Eckhart vehicle "Erased" and the well-received Noah Baumbach indie gem "Frances Ha."

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  • First movie to take in $100 million at the box office during its first weekend in theaters

    "Spider-Man," 2002

  • First movie to receive an X rating

    "Greetings," 1968

  • First non-erotic movie to feature full-frontal male nudity

    "Dante's Inferno," 1911

  • First major motion picture to use CGI

    "Westworld," 1973

  • Highest-grossing movie that never hit No. 1 at the box office

    "My Big Fat Greek Wedding," 2002 ($241.4 million)

  • First movie to show a toilet flushing

    "Psycho," 1960

  • First movie to gross $1 billion worldwide

    "Titanic," 1997

  • Highest-grossing movie on Christmas Day

    "Sherlock Holmes" 2009 ($24.6 million)

  • First color movie released in 3-D

    "House of Wax," 1953

  • First movie to have a score written specifically for it

    "The Assassination of the Duke of Guise," 1908 (composed by Camille Saint-Saëns)

  • First Hollywood movie to be released on DVD

    "Twister," 1996

  • First actress to be paid $1 million for a role

    Elizabeth Taylor, 1963 (for "Cleopatra")

  • First film broadcast on a major television network in its original, uncut format

    "The Wizard of Oz," 1956 (on CBS)

  • First vampire movie

    "Nosferatu," 1922

  • First film to use synchronized dialogue

    "The Jazz Singer," 1927