The reason we went up Mt Teide was to visit the astronomy institute. The conditions are ideal for earth-bound star-gazing, because there's the height (above clouds and pollution), the proximity to the equator, the surrounding ocean that keeps the atmospheric conditions stable and the generally favourable climate. Only Hawaii and Chile have similar situations, which is why they have telescopes, too.
I was surprised to learn that the telescopes are quite cheap. You can buy a standard 1-metre one for $100,000. OK, so setting it up and building the housing to put it in is more expensive, but still, if you're a rich person who wants one on your yacht, you can have one.
The guide kept telling us how great the sunset was. We were expecting to wait to see it, but our bus driver had other ideas as we had to be back for dinner in the evening. Still, on the way down we did stop at a particular spot that had a glorious view of three of the other Canary Islands with the sun setting over them.
As with most sunsets, it looked even better than the camera shows. The trip (90 minutes each way to the observatory) was worth it for this view alone.
The conference proper starts today. I've no idea what's happening, but that's fine because no-one else has, either.