A penny farthing bike is a 19th century invention that allowed people to get around cobblestone streets faster than walking and safer than its predecessor, the Boneshaker. It's often seen as the quintessential old-fashioned bicycle, with its giant front wheel, miniature back wheel, and tall seat at almost eye-level. They were designed and remodeled during the 1870s, until they caught on and propelled the bicycling craze of the 1880s.
The bike's name comes from the analogy of the large front wheel to a penny and the diminutive rear wheel to a farthing coin. The bike sits so high, it needs a mounting step to get up to the seat, called a hammock saddle. A simple brake works on the front wheel. The pedals are welded directly to the wheel, the way a child's modern tricycle works. To compensate for the lack of gears and a chain, the front wheel had a maximum circumference, such that your legs could work less and cover more ground. A penny farthing bike was measured in height, with models to compensate for children's stature, from around 30-60" (76-153 cm).
Someone may have chosen a penny farthing bike over a Boneshaker because its body was made entirely of metal, instead of wood. Another improvement was real rubber tires on the wheels, rather than plain wood wheels covered in iron that rattled, dented, or splintered. Even these improvements couldn't keep the penny farthing from causing riders to "take a header" and topple forward. The high center of gravity tempted the bicycle to tip whenever it hit another bike, a dog, uneven pavement, or a tiny pebble.
Not only did a penny farthing bike get people from place to place, it heralded the beginning of a bicycle club fad. Riders would join local clubs, purchase matching uniforms and hats, embroider the name of the club on their breast, and go on out on weekends. They would have races, contests, and obstacle course challenges. Cycling clubs also popularized bikes at a time when horse drawn carriages were competing for space on the road.
Some aficionados find classic, antique penny farthing bikes to restore, ride, or collect. There are even companies that make custom reproductions or original replicas that try to come as close as possible to the original bikes. They have formed clubs in America as well as Europe, complete with old-fashioned clothing and Sunday morning rides.