Harold Lloyd began in films as an extra before establishing himself as a comic actor for Mack Sennett and Hal Roach. He first gained popularity playing a Little Tramp knockoff, Lonesome Luke.

Far from a standard knockabout comic figure, Lloyd's "Glasses Character" became more human than Lonesome Luke, with a distinct personality - likable, romantic, a go-getter, and appealing in ways Chaplin's Tramp character could not be.

Harold Lloyd (with glasses) in "Lonesome Luke Loses Patients."

"I had the feeling that I would never get any farther with Lonesome Luke than I had," Lloyd once said in a TV interview, "because underneath it all, he was a comedy character that couldn't possibly rise to the heights that Chaplin had."

Lloyd shed the Lonesome Luke name and persona, but kept the spectacles.

Though his early films featured much slapstick, Lloyd helped create a genre of film in which daredevil thrills and comedy were mixed together – as when he tries to step off a streetcar onto a moving automobile.

The trick behind "Look Out Below" (1919), in which Harold Lloyd and Bebe Daniels are perched on a dangling girder high above Los Angeles, came about from a fortuitous bit of L.A. topography: the studio was built on the steep Hill Street, allowing for facades to be constructed that appeared (given the buildings in the distance) to be at a perilous height.

This photo shows Harold Lloyd and Bebe Daniels filming "Look Out Below," not very high above the ground. Director Hal Roach is at far left.

The trick was repeated in the 1920 film "High & Dizzy," in which a sleepwalking Mildred Davis leads Harold Lloyd onto the ledge of a building.

Shots of a stunt person on an actual building ledge intercut with the stars on the fake facade made the sequence even more believable.

Harold Lloyd reacts to the heights of his character's predicament in "High & Dizzy" (1920).

In "Haunted Spooks" (1920), Harold Lloyd's character decides to commit suicide, and consistently fails.

For "Never Weaken" (1921), in which Harold Lloyd's character winds up on a girder of a building under construction, a fake facade was created on the roof of the Ville de Paris department store in downtown L.A. The girders from a building being constructed down the street only added to the effect.

In "Why Worry" (1923), Harold Lloyd tries to help a giant with a toothache. But extricating the tooth attached to a rope proves hazardous to his own health.

Lloyd's most well-known film, "Safety Last!" (1923), was inspired after he watched Bill Strother, the "Human Fly," draw a crowd by scaling a building in Los Angeles.

Lloyd hired Strother to appear in the film, as a daredevil climbing a department store as part of a publicity stunt. Alas, Lloyd himself has to take the human fly's place.

Three different facades were built, on the rooftops of three different buildings of different heights, so that Lloyd would appear to be climbing progressively higher.

That's why the background street views appear to change, though one wouldn't notice, with all the attention on the man hanging from the clock.

The image of Harold Lloyd hanging from the hands of the clock is made all the more remarkable for his having lost his right thumb and forefinger a few years earlier when a prop bomb exploded in his hand. Lloyd wore prosthetic gloves to disguise his missing appendages.

"Human Fly" Bill Strother, dressed as Harold Lloyd's character, climbs the International Bank Building for "Safety Last!" A fake clock was placed on the building so it would match what was created for Lloyd's stunt.

A possible inspiration for "Safety Last!" was the 1919 short film "Ask Father," in which Harold Lloyd climbed up two stories of the same International Bank Building.

In "Hot Water" (1924), Harold Lloyd is out for a drive with his family, but the car gets away from him - and catching up to it doesn't mean the same as holding on.

A fine mess (from "Hot Water").

In "Girl Shy" (1924). Harold Lloyd is in a race against the clock to stop the wedding of his beloved. Streetcars are but a minor obstacle to true love.

Harold Lloyd and Jobyna Ralston in "The Freshman" (1925), in which a college man strives to make his bones on the football field without breaking them.

Harold Lloyd only made a few sound films, one of which, "Feet First" (1930), recreated the vertiginous acrobatics of "Safety Last."

Again, the daredevil scenes were shot not with rear-screen projection, but on rooftop sets using fake facades, high above L.A. streets.

Harold Lloyd in his last feature, "The Sin of Harold Diddlebock" (a.k.a. "Mad Wednesday) (1947).

For more info:

haroldlloyd.com (Official site)

"Safety Last!" (1923) - Available on Blu-ray/DVD from Criterion; Also available via digital download from Hulu Plus and iTunes