There are plenty of life lessons to be learned from Einstein's thought experiments — specifically, that there's value in daydreaming. And if, for example, you spend your days imagining what it'd be like if Mark Zuckerberg fought Elon Musk in the Colosseum, your dream might soon become reality. But before you book a flight to go witness the billionaire bout, you should be sure you're packing accordingly; Italy is introducing stricter dress codes for tourists.