See this ramp?
At first glance, it might look like a corridor where someone walked while the concrete was still wet, leaving behind footprints and numerous ruts.
Actually, this isn't the case at all.
What you see are footprints, yes, but they're caused by the asphalt being worn away by all the people who walk over them every year. And a lot of people walk over them, because it's the main corridor of the world's most visited tourist attraction: the Great Wall of China.
Around 10 million people visit this site every year, and considering that it has existed for over 2000 years, the total number of visitors is almost incalculable.