Selected as one of the top resources of 2015 for the classroom by the American Association of School Librarians, HSTRY is a free digital learning tool that enables teachers and students to create and explore interactive timelines in a simple way.
Originally, it was designed for historical timelimes but it seems perfect for project based learning and it is also interesting to create multimedia portfolios.
On Facebook: https://www.facebook.com/Hstry-255194477943075/timeline/
On Pinterest: https://www.pinterest.com/hstry/
On Twitter: https://twitter.com/HstryOrg
An example of timeline: