Start of the trail on the side of Arenal Volcano. After long dormancy, it erupted in 1968. Since then, it has been spewing red-hot boulders daily.

Orchids enjoy the thin soil on the volcanic rubble. They're among the first plants to gain a toehold.

Our guide started the walk off with a lesson on plate tectonics and volcanism. He and Marcia are standing on the Pacific Plate, unconcerned with subduction.

The very top of the mountain played peek-a-boo in the clouds and smoke. But we had very clear views during both the days we were there.

Looking the other way, Lake Arenal stands at the foot of the mountain. It's on the site of an ancient lake, and was re-dammed with material ejected in the 1968 eruption. It is now a major hydroelectric power source for Costa Rica.

This turkey vulture sat about 10 yards off the trail, waiting for one of us to break an ankle in the jumbled rocks, I suppose.