Palazzo Borromeo is the culmination of centuries of architectural evolution—an enduring masterpiece that has taken shape as a monumental residence designed for prestige and grandeur. Today, it serves as a Baroque art museum, housing an extraordinary collection of paintings, tapestries, sculptures, artifacts, and treasures that transport visitors into the splendor of bygone eras. 

The 20+ rooms of the palace are named to reflect their original purpose, such as the Conversation Room and the Ballroom, or take inspiration from the distinctive and valuable furnishings they contain, like the Medal Room, the Throne Room, and the Tapestry Gallery, which houses exquisite Flemish textiles depicting mythological scenes. Some rooms are named for historical events or illustrious figures who stayed within their walls, such as the Napoleon Room and the Queen’s Room. In 1935, the Music Room hosted the Stresa Conference, where world leaders gathered to address Germany’s violations of the Treaty of Versailles under Hitler. A typewritten account of the meeting remains displayed in the room as a testament to this momentous occasion. Also in this space, the right-hand wall commands particular attention, covered entirely with paintings by the Flemish artist Pieter Mulier, known as "Cavalier Tempesta." His dramatic depictions of turbulent seascapes and stormy skies were favorites of the Borromeo family, who invited the artist to live on the island, where he painted more than 80 works. 

The heart of Palazzo Borromeo is the Galleria Berthier, an extraordinary collection of over 130 paintings from the 17th and 18th centuries, a veritable museum within a museum. Alongside copies of works by Raphael, Correggio, Titian, and Guido Reni, the gallery also preserves original masterpieces of Lombard Renaissance art by Bergognone, Boltraffio, Crespi, Giampietrino, and Procaccini. 

The Salone Nuovo, the largest room in the Palazzo, is a luminous and stately space whose pale blue walls are accented with gilded stucco details, creating a sense of celestial elegance. Modeled on the church of San Lorenzo in Milan, the room is crowned by a domed ceiling bearing the Borromeo family motto, Humilitas. Four marble brackets, decorated with intricate inlays and supported by the main pillars, display family emblems: a seated camel (patience), a unicorn (devotion), a horse’s bit (strength), and a cedar tree (representing the Isole Borromee). 

The water-level grottos captivate with their creativity and originality. Designed to enchant visitors, they also offer a cool retreat during the summer months. Step into a marine-inspired world where walls, ceilings, and floors are adorned with pebbles, shells, marble, and fragments of volcanic rock. In these six grottos, every detail is meticulously arranged to form intricate patterns and decorative motifs. Along the way, you’ll encounter busts of heroes and deities, as well as display cases holding urns, vases, porcelain, and other treasures. From outside, the gentle lapping of the lake provides a soothing soundtrack.