3 Best Sights in Castelgandolfo, Side Trips from Rome

This waterside promenade—down a steep incline from the pretty town—is lined with restaurants, ice-cream parlors, and caffès and is a favorite spot for Roman families to relax on summer days. No motorized craft are allowed on the lake, but you can rent paddleboats and kayaks. In summer, you can also take a short guided boat trip to learn about the geology and history of the lake, which lies at the bottom of an extinct volcanic crater. The deep sapphire waters are full of swans, herons, and other birds, and there is a nature trail along the wooded end of the shore for those who want to get away from the crowds.

Deck chairs are available for rent on the small beach, and you can stop for a plate of freshly prepared pasta or a gigantic Roman sandwich at one of the little snack bars under the oak and alder trees. There's also a small permanent fairground for children, and local vendors often set up temporary shops selling crafts, toys, and snacks on the warmer weekends.

For centuries, the Apostolic Palace of Castel Gandolfo was the summer retreat of popes, who kept the papal villa and extensive grounds completely private. Luckily for tourists, Pope Francis decided that he was too busy to use it and had it opened to the public. Inside you can view the Gallery of Pontifical Portraits, ceremonial garments, and the imposing papal throne in the Sala degli Svizzeri. The private area of the palace with the pope's bedchamber, his library, study, and offices are also open to visitors.

In 2016, Pope Francis opened the 136-acre pontifical estate and its glorious gardens to the public, which includes the archaeological remains of the palace of the Roman Emperor Domitian (dating from the 1st century AD). To explore the gardens up close, a 50-minute ecobus tour of the villa grounds is available for €15 per person. The gardens are managed by Borgo Laudato Si', an ecologically minded department of the Vatican. As a result, in addition to the standard audio guide, each bus stop is accompanied by a short excerpt from the Encyclical Letter Laudato Si', the Pope's treatise on the natural environment.