If you’re staying around the Duoro, or maybe Porto, I’d really recommend this 5 hour roundtrip hike from the beautiful mountain town of Ermelo to the waterfalls in the heart of the Alvao National Park. Clearly signposted all the way, you’ll get some great views over the nearby mountains, walk through some of the gorgeous forest and reward yourself at the top with a swim in the natural pools and waterfalls. Best of all, you’ll have it largely to yourself as, from what I saw, there are only see a few people along the way.
Overall a great hike for a break away from the various wine tours!