A few years back, I was spending the afternoon in a small Caribbean town when I met a teenager who offered to take me down into a nearby canyon.

Was it too risky? No, I thought: I was in good shape, the kid seemed innocent enough, and the canyon was actually pretty small. (I’m not even sure it was technically a canyon.) So I went. Everything was fine, although there was no real path and I struggled mightily on the way back, grabbing onto roots and rocks made slippery in a drizzle.

I had been wrong. It was too risky, but I simply wasn’t aware of the risk. When it rains, flash floods can trap and drown hikers who can’t scramble up the steep sides fast enough.

The biggest danger to travelers is not knowing what’s dangerous. We can all agree that staying out of war zones, avoiding perilously overcrowded ferry boats, and steering clear of Ebola vectors are all good ideas. But what about avoiding destinations that have recently suffered terrorist attacks?

It turns out that won’t do you much good, statistically speaking. You’d be better off going to that same place but renting a bigger car, ignoring a friend’s bad advice, and always carrying a $100 bill in your wallet.

That’s because relatively few tourists die in terrorist attacks. According to the US State Department, which keeps track of how many American civilians are killed abroad, only four died in terrorist attacks from January to June of 2018 (the latest numbers available). And none was a tourist. They all died in the same place on the same day: the Intercontinental Hotel in Kabul, Afghanistan, hardly a popular travel destination.

The most common cause of death in that period was motor vehicle accidents. Eighty-one Americans died everywhere from Australia to Macedonia to Guadalajara, Mexico. The second most common cause of death was drowning: 71 deaths from Iceland to Tel Aviv to Cancun. (It’s not clear whether any were caused by flash floods in a canyon.)

So if you really want to reduce risk, pay a few extra bucks to rent a solid car with a good safety record instead of a flimsy subcompact. Think twice before taking rickety buses over mountain passes with no guard rails. And put on your seat belt even if no one in the entire country uses seat belts. Don’t swim in areas with no lifeguards, and definitely don’t swim in areas with NO SWIMMING signs.

The third most common cause of death for that period were homicides, totaling 63 victims. It’s impossible to tell how many were expats and how many were travelers. But it was certainly more than four. That’s why finding accurate information on crime rates in destinations you’re considering is so important. But many people simply ask friends — or travelers in online forums — if the place seemed safe when they went. Those friends often say, “I was there and nothing happened to me, so you’ll be fine.”

You don’t have to be a probability mastermind to see the flaw in that argument. They might as well have said, “I crossed Times Square blindfolded during rush hour and nothing happened, so you’ll be fine.”

If you do hear a place is known for muggings or street crime, that’s when carrying a $100 bill is worthwhile. For that, and several other surprising strategies, you’ll have to watch the video.

Seth Kugel is the author of Rediscovering Travel: A Guide for the Globally Curious, out this week from Norton. He was formerly the Frugal Traveler columnist for the New York Times.