Website: https://www.mindmup.com/
Google Apps for Education app: https://apps.google.com/marketplace/u/0/app/mkgkheknpfngchmoaognoilfanomldfl
Google Chrome app: https://chrome.google.com/webstore/detail/mindmup-20-free-mind-map/mkgkheknpfngchmoaognoilfanomldfl
Website: http://www.youtube.com/teachers