The Palace of the Marquesses of Fronteira near Monsanto forest park is one of the most stunning spots in Lisbon. It's a 17th-century palace with lush gardens that you can explore. You can't wander everywhere 'cause it's still the Marquesses' pad, but the gardens are open to the public. And let me tell you, they're something else. There's a pond with black swans, cool sculptures, and this epic wall with stairs where you can climb up and check out statues of the Kings of Portugal. Plus, there's this rad chapel covered in seashells and stuff.