This chapter aims to connect the digital resources of knowledge with the historical and cultural heritage in the context of smart cities. Specifically, combining the joint intervention in the Real Sitio of El Pardo and Aranjuez, as well as the Foundation Square of the University of Alcalá, both in Spain. Through traditional historical research and the innovative use of new technologies like augmented reality (AR), a historical, biological and cultural heritage is conserved, consisting of forests, gardens, agricultural spaces, urban centers and palatial residences. Cultural and artistic heritage is a resource of the first magnitude for the sustainable development of smart cities. It evolves with time and society; it is this that determines what goods are to be conserved and protected for posterity, according to the values attributed to them. Hence, the importance of achieving an awareness in society plays an active part in the conservation, enjoyment and dissemination of heritage. In this context, the augmented reality is presented as a powerful tool for contextualizing and disseminating the heritage, as well as to make the resources created more accessible, making an innovative use of the new technologies applied to the transfer of knowledge and the enhancement of a country's cultural and historical heritage.