In most countries, $100 USD can be a lifesaver in an emergency—whether it’s for a last-minute visa fee, a surprise “tip” that you need, or your way quickly out of a bad situation. I recommend keeping two separate stashes of $100 in $20 bills, hidden in different spots in your luggage or on your person. That way, if one goes missing, you’re not completely out of luck—and you won’t have to awkwardly beg a stranger for cash on any airplane (trust me on this one).