But today, in our modern high-rise environment, if you simply want to go up or down, it's probably fair to say we've actually devolved. Stairs, elevators, and lifts all take up precious space within buildings, and they're expensive, complicated, or require endless maintenance. Now a new human-powered system prototype dubbed Vertical Walking has been developed that requires just ten percent of the effort needed to climb stairs, but can easily move a person up a vast number of floors.