The document discusses border security technologies used in Europe, including the Schengen Information System (SIS) and Spain's SIVE border surveillance system. The SIS is a database containing information on persons banned from entering Europe or wanted for criminal offenses that is used at airports and for visa issuance. Spain uses the SIVE system of radar stations, control centers, and interceptor units to monitor its maritime borders and detect migrant vessels. The development of these technologies has made borders invisible and shifted surveillance to data collection and information sharing between countries.