Objective: The objective of the ACube (Ambient Aware Assistance) project is the development and testing of an advanced monitoring system to support professional caregivers in nursing home and residential care facilities. The goal of the system is the detection of events potentially dangerous for the guest of nursing homes, or interesting for the health care professionals, and the development of an appropriate response. Design: The prototype developed during the project relies on distributed sensor networks connected to an automatic reasoning system. Sensing technologies used for collecting environmental data include video cameras, RFID antennas, microphones, and wireless sensor networks. Wearable sensors for detecting biosignals (such as electrocardiogram, actigrafy and breath) are also used. The data acquired from the sensors are analyzed by the automatic reasoning system that identifies potentially dangerous situations and alerts the caregiver. Results: The developed prototype has been deployed into two test site: one in Trento, and the other in Milan (within the smart home facility of the DAT service). Several scenarios have been tested where the ACube prototype proved to be able to identify relevant events such as a repetitive walking pattern, the proximity to dangerous areas (e.g. an open window), health problems (e.g. tachycardia), etc. Conclusions: By supporting the professional caregivers the ACube system could contribute to the improvement of the quality of services provided by nursing homes and residential care facilities while reducing the costs. In the future, the system could also be exported to different application domains, such as the intelligent monitoring and surveillance of public spaces (museums, schools, stations).