Paul L.
Yelp
At over 12,000 feet, this volcano, Teide, is the highest point in Spain.
You can take a cable car (last one up at 4 pm) up to the top and the views from the top are beautiful.
The last car down is at 5 pm, though there are guides up at the top to warn you when to get back. Otherwise, you can hike up or down, though you'll need a full day.
It's 25 Euros, but well worth it. You can book online if you want to avoid the ticket lines.