From the sea we saw many sights like this - volcanos in the distance. Of course the Galapagos Islands were formed by volcanic action, the oldest islands about 3 million years ago and the youngest about 700 thousand years ago, so there are volcanos everywhere. One very large lava field was less than a century old, too young to have much plant life on it.
Some of the volcanos have eroded away leaving just jagged rings of rock, like this one called the Devil's Crown. Roger snorkeled halfway around it (perhaps 1/4 of a mile) on this rainy and blustery day, seeing some pretty fish but for the most part fighting the currents and wondering where the rescue boats were and thinking about survival! Some of the snorkelers went around the other half of the ring but others, like Roger, opted out, having had enough adventure for the day. The ones who did go were treated to the sight of some sharks, though they were lazy sharks and had to be chased out of their underwater cave by our guide, Charlie, for the benefit of the tourists!
This spot, a high spot in a volcanic region, provided a really wonderful view of the area. The sharp rock at the right is shown below, close up.
Here is that same rock, with a tour boat on the water near its foot for scale.
Coming down from the high point (300 or so stairs) we passed through an area that was very bleak and looked, we suppose, like the moon. Pretty though!
Some of the volcanic rock is full of bubbles and is surprisingly light, so here is Roger holding up two rather large rocks, but without very much effort in fact.
The volcanic area is very dramatic, and you can almost see the action which must have taken place as the lava cooled. Near the top of the picture is a small lava tube, formed when a river of lava freezes over where it contacts the air, thereby insulating the lava underneath which contines to flow, in the lava drainpipe so formed. Something happened later to expose this cross section of the small lava tube.
However, some of the lava tubes are huge. We entered this one and went into it for some distance, until it ended at the water.
We wondered why the beaches were usually beautiful white sand, while the rocks around the beach (and most of the rocks everywhere) were black volcanic material. Eventually we found out that the beaches are mostly built up of particles from coral reefs. On one beach we found this process in an early stage, and there were many chunks of coral on the beach - eventually to turn into beach sand.