Sintra is located near Lisbon, the capital city of Portugal. Sintra has been listed as a UNESCO World Heritage Site because of its 19th-century ravishing architecture and landscapes. It's dominated by precipitous mountains and fascinating forests.
If you feel like your feet is burning, then you should try trekking. Trek is a long journey full of adventure. It is undertaken on foot in areas where there are no buses, or train or any other mean of transport. So, if you want to explore the nature on foot, then Sintra hills are a good choice.
Discover the beauty and mystique of Sintra and the treasure that is hidden in the woods. You can start from Cascais national park and discover beautiful coastal trails. You can trek along the coast with dunes as well as cliffs across the mountains of Sintra. You’ll have the opportunity to see the Moorish Castle, dating back to the 8th Century.
Pena palace is also one of the reason to visit Sintra and have the opportunity to explore paths that lead to one of the highest mountain ridge. The distance for this trekking tour is approximately 34 km/21 mi. Between 1 to 5 the difficulty is 3.  If you don’t want to have a self-guided tour, then you can find lots of organized trekking tours.
In Sintra there are other activities you can do on you spare time, and lots of accommodation options.