4 incredible sites to learn and earn certificates from Top-Notch Universities for Free!

The Udacity Course Experience
Udacity’s online courses are rigorous and may even make you sweat. You’ll tackle projects built by tech leaders like Google, AT&T, and Intuit, to develop relevant industry skills. You'll stretch yourself while our Coaches support, mentor, and cheer you on every step of the way to your newly minted certificate.
https://www.udacity.com

Eliademy, your new virtual classroom.
Eliademy supports educators and students with free online classrooms that enable them create, share and manage courses. Universities, colleges, trainers, coaches, hobby clubs among others can use it as a free learning management system and course content created by the teacher will always belong to them.

https://eliademy.com

Coursera! Take the world's best courses, online, for free.
Coursera is an education platform that partners with top universities and organizations worldwide, to offer courses online for anyone to take, for free.
https://www.coursera.org

EdX: Based in Cambridge, Massachusetts. Governed by MIT and Harvard.
EdX offers interactive online classes and MOOCs from the world’s best universities. Online courses from MITx, HarvardX, BerkeleyX, UTx and many other universities.
https://www.edx.org