This is a made-for-the-tourists restored fort. Ramon said they’d rebuilt it a few times already. Here we see an example of the adobe construction that grew up around the Europeans, not a native technique but cheap and useful.
The Spanish first came here in 1584 but they all starved to death. Then in 1843 the Chileans sent a schooner manned by the islander Chilotes and an English officer to occupy the area and they were pretty much driven out by the elements too. And as was so often the case everywhere, the few indigenous people all died of European diseases.