Developing successful multimedia systems is challenging as it involves integrating different media types into a coherent framework. Continuous media like video require large storage and bandwidth while automatic analysis of audio, image and video content is difficult. Multimedia computing draws from many areas and requires complex algorithms and efficient hardware. Example multimedia systems at MIT's Project Athena included applications for real estate, navigation, learning and photos sharing. Key techniques in multimedia include data compression, processing and analysis, delivery over networks, and database indexing and retrieval.