It was in the mid-18th century that Manuel Telles da Silva, 1st Marquis of Alegrete, had his summer manor built, complete with garden and palace. Over the centuries, the building underwent changes until, in 1983, it became the property of the Santa Casa da Misericórdia de Lisboa.

One of the Holy House's main concerns during the first phase of this work was to guarantee the integrity of the constructive and artistic elements, respecting the original materials and restoring decorative details, especially the frescoes.

According to the Directorate-General for Heritage (DGPC), this is a two-storey palace, "late Baroque with a rectangular longitudinal plan", built in front of a field of mulberry trees, and decorated with "ashlars of Pombaline tiles, using the sponged technique, and neoclassical tiles, with plant patterns".

The DGPC also emphasises the "neoclassical mural paintings on the walls and ceilings, some in trompe l'oeil [an artistic technique that creates an optical illusion], of stucco on a curved moulding, with geometric and phytomorphic elements, architectural and mythological details, birds and fruit". These elements "have affinities with the mural paintings at Quinta da Francelha [in Loures] and the Palácio dos Marqueses de Angeja [now the Museu Nacional do Traje, in Lumiar, Lisbon] and with the Casa Nobre da Rua de Avis [in Évora]". In the garden area, the DGPC emphasises the "benches-conversadeiras lined with tiles, forming a viewpoint over the property", and the artificial lake.

The exhibition "Quinta Alegre - From People to People" can also be visited, showing all the phases of this major refurbishment project, as well as a brief history of the quinta, the valences and concepts that integrate and explain this emblematic work.

The Jardim da Quinta Alegre or Campo das Amoreiras was designed from the former grounds of Quinta Alegre, also known as Quinta dos Marqueses do Alegrete, as a leisure garden for the residents of the parish of Santa Clara.

It represents a large triangular plain with 24,500 square metres of grass, bordered by trees all around its perimeter. Long straight and curved paths, constantly flanked by trees, cross the children's playground and the small open-air amphitheatre. Opposite these structures is a bandstand and, in the centre of the garden, a round landscaped area with a different layout.

It is located very close to Lisbon Airport's runway in the parish of Santa Clara, on the outskirts of Lisbon.