The Alps are an expansive mountain range located in Europe that spans across eight countries: France, Switzerland, Germany, Italy, Austria, Monaco, Liechtenstein, and Slovenia. Some countries have more Alps than others. Switzerland is the most Alpine of all the eight Alpine countries. The Alps cover 65% of Switzerland, making this tall mountain range an important feature of the Swiss landscape and culture.

Mountain climbing is a popular sport in Switzerland. The International Climbing and Mountaineering Federation (UIAA) measures and defines the different types of mountains all over the world. In the Alps, there are 82 four-thousanders, 48 of which are in Switzerland. A four-thousander is a mountain that is 4,000 meters (13,123 feet) above sea level. By the way, only Americans use feet to measure the height of stuff like mountains. The rest of the world uses meters and so will I for the rest of this article.

Let me tell you a bit about myself: I’m more of a beachy, sealevel type of girl, not a climb-every-mountain type of girl. But when we were traveling in Europe, my friend Kim convinced me to climb a four-thousander in Switzerland with her.

Well, Kim took pity on me and she took me up an “easy” mountain called the Breithorn that’s on Switzerland’s southern border, right near Italy. The climb is considered easy because the Klein Matterhorn cable car takes climbers up most of the way (3,880 meters) to the top of Klein Matterhorn, which is a mountain right next to Breithorn. The ride up Klein Matterhorn is truly breathtaking: You rise over pine trees and quaint wood cabins. The sky is bright blue and the snow is blinding white—I imagine this is what the setting of the story of Heidi looked like.

We got to the top of Klein Matterhorn and started the preparation for our ascent, or climb, up the Breithorn. We paid to go as part of a professionally led, guided tour and rented crampons and ice picks to help us climb up the icy mountain. Crampons are kind of like cleats that you strap to the bottom of your boots, only instead of rubber nubs, the cleats are metal spikes that help you not slip off the mountain and die. We also rented some warm weather gear because it was much colder up there than we’d expected.

While we were getting ready, I started to get a headache. I felt very light-headed, too, like I couldn’t catch my breath. The group leader explained that the higher the altitude, the less oxygen there is in the air. That means for each breath you take, your body is getting less oxygen than at sea level. When you first get to a high altitude, your body suffers from oxygen deprivation (in other words, it’s not getting enough) and you can start to feel ill—this is called altitude sickness, and some people get it worse than others. At 3,000 meters, the air starts to get pretty thin. We were now at more than 3,800 meters and the air was very thin and my body was feeling it.

But Kim was pretty pumped about the hike, so I swallowed my complaints and went along. The group leader told us to drink lots of water to help with the altitude sickness. I suppose that means that oxygen deprivation can also dehydrate you. Well, I did my best, but the round trip hike was supposed to last between three to four hours. Guess who didn’t make it past an hour and a half? Nope, not me—it was Kim. But I’m a good friend, so I stayed with her.

About 30 minutes into our ascent, my whole body hurt, kind of like when you have the flu. At the 90-minute point, Kim sat down on a ledge and said she couldn’t go any farther. Luckily, Kim wasn’t the only one. A group of five or six of us was told to sit or lie down and relax. We lay in the ice looking up at the sky and wondering if this is where it all ends. The assistant guide let us rest for about an hour and then led us carefully down the mountain. I was so exhausted and sick by the time we reached Klein Matterhorn that I threw up (just another fun symptom of altitude sickness). I guess you could say that I left my mark in the Swiss Alps.

After rinsing my mouth with water, I was able to tell Kim, “Next time, we go to Hawaii. The Swiss Alps make me sick.”