And, unless you're Spider-Man (or Lynn Hill, the first person to free climb El Cap), you have to resort to aid to ascend it.

WSJ: Training for the Big Wall | By Michael J. Ybarra

It is currently free to climb the 334 steps of the clock tower containing Big Ben.

BBC: U-turn over Big Ben trip charges

Far from a zero-sum game, where the successes of some come at the expense of others, free economies climb spirals of mutual gain and learning.

FORBES: The Wonders of Wealth, the Path Out of Poverty

They are free to climb.

NEWYORKER: The Disconnect

You could probably free solo the same climb in 10 minutes.

WSJ: Training for the Big Wall | By Michael J. Ybarra

The users it has registered to its, mostly free, internet access services, will climb to 10.7 million from 6.8 million after the Liberty Surf takeover.

BBC: Italy's Tiscali buys Liberty Surf

At the time of writing, Hill Climb Racing is the most popular free game in the United States and in several other countries, and it is in the top 10 chart of free games in nearly every country of the western hemisphere.

FORBES: Connect

The U-shaped recovery in the U.S. means the economic free-fall has been arrested, but no strong climb back up to growth has yet begun.

FORBES: Magazine Article

Heading south, forego the tourist boat-tours to Liberty Island and instead climb aboard the Staten Island Ferry, alongside the commuters, for a terrific view - free of charge - of Ellis Island, Lower Manhattan and Lady Liberty herself.

BBC: Summer in the city: New York

Its staff are required to climb out of helicopters to do the job - it is easy to understand how a hands-free computer would be useful in these circumstances!

BBC: Motorola unveils a computer that straps onto your head