Thanks to its microscopic budget and major success at the box office, the 2007 film Paranormal Activity, scored a return on investment of 19,758 percent, absolutely blowing away the next most profitable film (2015 horror film Gallows, with an ROI of 6,843 percent). It cost just $60,000 to make and another $400,000 or so to market, yet ultimately brought in more than $89 million.

The best-known line from Jaws ("You're gonna need a bigger boat," not "We're gonna need a bigger boat," as it's often misquoted, by the way) was not in the actual script. Actor Roy Scheider said it throughout the filming, joking about the small boat the producers had selected to hold the filming equipment, and it ended up in the final cut.

Speaking of Hannibal the cannibal, while Anthony Hopkins turned the crazy-smart serial killer into an unforgettable cultural touchstone, the role was originally supposed to go to Gene Hackman, who bought the rights to The Silence of the Lambs and had planned on directing the film himself. He backed off the project when he decided that the role was too dark for his taste.

The original script for Butch Cassidy and the Sundance Kid, by William Goldman, was originally titled The Sundance Kid and Butch Cassidy. That all flipped when Paul Newman, maybe the biggest star on the planet at the time of production, took the role of Butch.

A lot more, in fact. The canine actor earned $125 per week for his efforts, while the actors playing the Munchkins brought in just $50 a week.

The animators who created the pack of balloons in Up actually created every single one. The film's effects artist, Jon Reisch, told Tech Radar, "The entire canopy is filled with balloons. We didn't just simulate the outer shell." And they even got a specific count of exactly the number of balloons: 10,297.

In that famous poppy-field scene in Wizard of Oz, the snow coming down is calming to Dorothy and her posse. But they should probably have been far less relaxed as these were actually asbestos-based fake snowflakes—a popular Christmas decoration throughout the United States and Europe at the time. Wicked, indeed.

The terrifying noises made by the raptors in Jurassic Park were sourced from recordings of tortoises mating. The sound designer also experimented with horses breathing and geese hissing, but the tortoises proved the most evocative.

The two instant-classic pseudo-westerns of 2007 were filmed in the same area of Marfa, Texas, around the same time, which created issues when a pyrotechnical test for There Will Be Blood created a huge smoke cloud that got into the shot for No Country For Old Men. Joel and Ethan Coen had to wait for it to dissipate before they could get back to shooting.

 

A command entered in the "master machine" where the animation for Toy Story 2 was stored deleted 90 percent of the work the Pixar team had done on it. As Mental Floss describes, "A plan was quickly hatched to restore the data from a regular backup, which meant that only half a day of work would have been lost. But the backup system had failed. Pixar, incredibly, did not have a copy of the Toy Story 2 files on its servers." Fortunately, the film's technical director had a copy she had been working on from home, and much of it was restored.

Jules' wallet in Pulp Fiction that reads "Bad #&$&*@$" actually belonged to the director—who picked it up because of its reference to the 1971 film Shaft. As it happened, Samuel L. Jackson would go on to play the character that inspired the wallet in the 2000 remake of Shaft.

At a time it was considered inappropriate to show a toilet being flushed on screen, Alfred Hitchcock saw an opportunity to add some extra shock to his already shocking film—presenting a scrap of paper, which proves an important clue, failing to flush in a toilet. In the book, the clue was an earring found in the bathroom, but Hitchcock changed it to a piece of paper actually in the toilet, partly to add an extra jolt for viewers. 

After the success of the 2007 film telling the story of the lovable, culinary-inspired vermin, kids everywhere asked their parents, "Can we get one? I promise I'll take care of it." At least one domestic pet chain saw sales of pet rats jump 50 percent after the movie's release. We wonder how many of those rats immediately became parental responsibilities…

Though it would quickly cruise its way into film history, the script for Taxi Driver came together in just a few days. As screenwriter Paul Schrader told The Hollywood Reporter, "I crashed at an ex-girlfriend's place, and I just wrote continuously. The first draft was maybe 60 pages, and I started the next draft immediately, and it took less than two weeks."

That slightly scandalous charcoal drawing of a topless Kate Winslet in Titanic was drawn by none other than the director himself, James Cameron. If you want something done right, sometimes you just need to do it yourself. 

 

Though now famous as the piano player at Rick's Café Américain, Dooley Wilson, the actor who played Sam, was an experienced musician and bandleader—but not a piano player. He was a drummer and mimed the piano playing. "As Time Goes By" was dubbed in later.

Just as there was a run on pet rats, the population of clownfish in their natural habitats took a precipitous drop following the release of Finding Nemo, which stars a clownfish. Marine biologists reported that the numbers of the fish dropped by as much as 75 percent in the Australian reefs they inhabit.

While the Alien franchise swaps in different androids for (almost) every installment, there is an interesting consistency to them: they go in alphabetical order. Ash, Bishop, Call, and, most recently, David (played by Michael Fassbender in Prometheus and Alien: Covenant).

In November 2015 the Museum broke a modern record. Mapped out and presented digitally, the Museum became the largest indoor space on Google Street View. You can explore it at your leisure from the comfort of your own home (or the discomfort of the bus, or anywhere really), plus there are stories of thousands of highlight objects at the Google Cultural Institute.

The British Museum is the world’s oldest national public museum. Founded in 1753, it opened its doors in 1759, 17 years before the Declaration of Independence. It was free to all ‘studious and curious persons, and it’s still free today (but a few other things have changed).

MIND THE GAP! That’s the gap between when there was a British Museum tube station and now. The photos above (courtesy of London Transport Museum) show the entrance to the Museum’s underground station in 1921, some gentlemen waiting on the platform in 1903 (with some fabulous hats!), and its construction in 1898. The station opened in 1900 but was closed in September 1933 when the new Holborn station opened, less than 100 yards away.