5 . I like challenges, but this one was almost too difficult. I had begged Mom to take me on a completely new adventure for my sixteenth birthday. Now, here we were, just Mom and me with our guide, Milo, standing on the shore of Lake Arenal in Costa Rica.

Milo helped us onto our horses. Getting on the back of my horse was difficult, but controlling it was a little easier. We started on our ride. The guidebook said we would cross three rivers. As we tried to go through a gentle stream, I asked hopefully, “Is this the first river?” “I don't think so, Katie,” Mom said.

Soon enough, we came to a real river. I felt sick to my stomach when I saw that the far shore was half a football field away! The four-foot-deep river flowed over large rocks. So much for dry shoes or jeans.

After two more rivers, the path got steeper and muddier. The rainforest was splendid and absolutely beautiful. But I wondered whether my horse could keep its balance in knee-high mud. Three frightening hours later, we came to a corral (畜栏). I wondered whether we were stopping. To one side was a wonderful view of the lake and volcano, and to the other, a brightly painted restaurant. “OK,” I laughed nervously. “That was frightening, but I'm so glad we did it! ”