Or at least the epic struggle to make an earth sandwich without getting the bread soggy. Where on earth could you put a piece of bread, on dry land, while having a bit of dry land on the other side to put the other piece of bread on?
The world is a lot sloshier than we imagine it to be. Over two-thirds of it is covered with water, and what's left is meted out in random dribbles across the globe. In most places, if you were to stand on land and peer through the earth to see what was on the other side, you would see nothing but ocean, and perhaps a few people on yachts asking you to please give them some privacy. The way the continents are configured, it's very hard to find a spot on solid ground that has an antipodal complement.
In 2006, blogger Ze Frank proposed a challenge: make an earth sandwich. Slap a piece of bread on one piece of land while at the exact same time, another person slaps another piece of bread on the land directly opposite your piece. In the age of the internet, that doesn't sound that hard. Unfortunately, land groups together. The Wikipedia antipodal map above shows the problem. For one thing, the entire lower 48 United States are out. There just isn't anything on the other side of the globe. And if you look up at Alaska, as well as Canada, Greenland, and northern Asia, someone living there could only sandwich the world with the help of someone making a trek through Antarctica. And those people can't afford to waste good bread. South America and China had a good shot, but the first people to sandwich the earth were in Spain and in New Zealand. Timing everything right, one person clapped a piece of bread to the ground in Spain while a temporary New Zealand resident took a piece of bread to the earth there.
(Rumor has it, though, that is was a long loaf of French bread, which means it might not have been a sandwich so much as an X. But possibly people like it that way.)