In this paper, we describe CHIS (Cultural Heritage Information System), a big data infrastructure that can be used to query, browse, analyze and process digital contents related to cultural heritage from a set of heterogeneous and distributed repositories. CHIS is characterized by the following technical features: capability to gather information from distributed and heterogeneous data sources (e.g., Sensor Networks, Social Media Networks, Digital Libraries and Archives, Multimedia Collections, Web Data Services, etc.); advanced data management techniques and technologies; ability to provide useful and personalized data to users based on their preferences and context; advanced information retrieval facilities, data analytics and other utilities/services, according to the SOA paradigm. By means of a set of ad-hoc APIs, and value-added data processing and analytics services, our system can support several applications: mobile multimedia guides for cultural environments, web portals to promote the cultural heritage of a given organization, multimedia recommender and storytelling systems and so on. We discuss the main ideas that characterize the system, showing its use for several applications.