TimelineJS is an open-source tool that enables anyone to build visually rich, interactive timelines.
How to Use TimelineJS from Northwestern U. Knight Lab on Vimeo.
Instructions are available directly from TimelineJS explaining the four steps to create and share a timeline.
Preceden (formerly Timeglider) is a web-based visual timeline software for creating and sharing history and project planning. Their free plan allows you to create unlimited timelines; add 10 events per timeline; and export to PDF, PPTX, & more.
Sample projects:
Tiki-Toki is a web based program for creating interactive, online timelines with images and brief data points.
Sample projects: