When I was a graduate student, I studied the rain forest in Costa Rica. I was studying how climate influenced tree growth. Sometimes, I had to take measurements of leaves in the forest canopy. Using a crossbow, I would send a rope into the top of a tree. Then, with my instruments, I would climb 150 feet up the rope to the tree canopy. At the forest floor, only 3 percent of sunlight comes through. It is dark and gloomy there. I would slowly inch my way up into the bright, sunny, breezy canopy. I could see all kinds of wildlife up close. I saw toucans, parrots, monkeys, and butterflies. When I was finished, it was fun to rappel back down.