It began on October 7, 1913 when engineers constructed a crude system using a rope and winch to pull a Ford Model T past 140 workers in a sprawling new factory dubbed the Crystal Palace.
Henry Ford launched the modern assembly line in a suburb of Detroit a century ago -- and helped spark a radical transformation of both manufacturing and society.
By drastically reducing the cost of production with standardized parts and more efficient assembly, Ford was able to bring the luxury, convenience and freedom of the automobile to the masses.
Other industries soon adopted the innovation and today, everything from cereal to caskets is made on assembly lines.
"It had a huge, huge impact," said Stephen Burnett, a professor with Northwestern University's Kellogg School of Management.
Standardization led to lower costs, higher quality and more reliable products.
Most critically, the assembly line cut the amount of time it took to assemble a Model T from 12.5 hours to just 93 minutes.
"Any time you increase the productivity of labor, tremendously valuable things can happen to the economy," Burnett told AFP.
Higher productivity means more profit, some of which is often returned to workers through higher wages. Workers then have more money to buy products, creating what economists call a virtuous cycle of growth.
The assembly line also changed the way people worked and lived, accelerating the shift from rural areas to cities, and increasing the number of people doing repetitive, low-skilled jobs.
From 100 to 1,000 Model Ts a day
While piece work was a time-honored tradition and the moving assembly line had already transformed the meatpacking industry in Chicago and Cincinnati, it was Ford who found a way to make it work for complex manufacturing.
"Henry Ford said if I could save every one of my workers 50 steps a day then I could save miles by the end of the year," said Bob Kreipke, Ford's corporate historian.
Ford had already cut costs by standardizing the vehicle and its parts -- the Model T was famously available in any color the customer wanted, so long as it was black.
But the cost was still too high and the volume too low for the "great multitude" he hoped to reach.
That changed with the assembly line he launched in Highland Park.
Trains filled with parts rolled down the main bay of the Crystal Palace, where cranes slid through the sunlight pouring in from a glass ceiling and lifted the parts up to balconies. Conveyor belts and gravity wells carried parts to workers as cars were pulled from floor to floor.
"It was a beehive of motion when it was in play," Kreipke said as he toured the historic plant Ford now uses for storage.
"When he first started he made about 100 cars a day and it got up to 1,000 -- which is almost the same as a modern factory."
In 1914, Ford's 13,000 workers built around 300,000 cars -- more than his nearly 300 competitors managed to build with 66,350 employees.
Lower prices, empowered workers
The specialization of the assembly line meant that Ford no longer had to use craftsmen and could instead hire low-skill workers and teach them a few simple steps.
But the monotonous work led to high turnover, leading Ford to double his minimum wage in order to keep his line humming.
The five-dollar day was eventually followed by the five-day work week, which meant Ford workers had both the money to buy his cars and the leisure time to use them.
Despite the higher labor costs, Ford's efficiencies allowed him to eventually lower the price of the Model T from its introductory rate of $850 to $260.
Technological innovations like automation and just-in-time delivery have brought further efficiencies.
New technologies, 100 years on
Today, just 500 people work directly on the assembly line at Ford's Michigan Assembly Plant, which now builds 605 Focus and C-Max sedans in each of two 10-hour shifts. Some 48,000 people worked at the Crystal Palace at its peak.
The flexible line builds five different models -- a high performance, a hybrid and a standard Focus plus the hybrid and plug-in hybrid C-Max -- with a range of colors and features, including a hatchback option.
A complex computer system tracks each vehicle as it makes its way down the line, matching engines to bodies and letting workers know when it's time to swap parts or press a different badge onto the frame.
Hydraulics lift the car and the heavier parts so workers don't have to stand in pits or strain themselves, and robots handle the most precise work like welding in the body shop.
"If Henry Ford came right now in a time machine, he would be very proud of the workforce here and be very proud of what we've done with his manufacturing process," said David Torosian, who manages the plant.