Sayyiduna Ibn Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "When Allah created the Garden of Eden (Jannat Adn), He created in it what no eye has seen, no ear has heard, and has never occurred to the heart of any human being. Then Allah said to it: Speak. And it said: 'Indeed, the believers have succeeded.'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11391