<p>The study presents the results of architectural and vegetation survey missions in the UNESCO site of <i>Quinta da Regaleira</i> in the city of Sintra, Portugal. The different types of connecting elements of the epigean and hypogean architectures in the Park are analysed through the disciplinary tools of architectural design. Surveys and models of some of the connecting elements are proposed for an understanding of the site and its subsequent protection and valorisation through digital documentation. Of great interest is the architectural and social relationship that the site establishes with the city of Sintra.</p><p>The survey of epigean architecture considered the following: the <i>Casa da Renasceça</i>, the <i>Capela</i>, the <i>Cocheiras</i>, the <i>Estufa</i>, the <i>Oficina das Artes</i>, the <i>Loggia dos Pisoes</i>, the <i>Casa dos Ibis</i>, the <i>Torre da Regaleira</i> the <i>Terraço dos Mundos Celestes</i> and the <i>Fonte da Abundância</i>.</p><p>The survey of underground architecture considered the following architectures: the <i>Gruta do Labirinto</i>, the <i>Gruta da Leda</i>, the <i>Lago da Cascata</i>, the <i>Gruta do Aquario</i>, the <i>Gruta do Oriente</i>, the <i>Portal dos Guardiães</i>, the <i>Poço Imperfeito</i> and the <i>Poço Iniziático</i>.</p><p>The work constitutes a complete and accurate analysis, represented through technical drawings, in different scales, digital point clouds and 3D modelling for the visualisation of the architecture in the <i>Quinta da Regaleira</i> in Sintra.</p>