TCKnowledgeGraph is a sample iOS app uses the API provided by Freebase to search and fetch topics from its knowledge graph. This app also makes use of the Wikipedia API to pull in images that are currently missing from Freebase’s database.
What is Freebase?
Freebase is a free and open knowledge graph of over 39 million topics and 1.8 billion facts. It will continue to improve and expand as the community contributes more data.
Freebase provides an API that allows developers to build apps that makes use of its massive knowledge graph. In fact, Google Knowledge Graph uses Freebase as one of its data source.