There are lots of tools out there for building interactive timelines, but my two favorites are Dipity and TimelineJS.
Dipity has been around long enough that it was the platform for one of my first digital storytelling projects, which documented New Hampshire residents who died while serving in Iraq and Afghanistan.
TimelineJS is newer, and I’ve quickly grown to love it because of its polished look. It’s been used for several notable stories, including this money laundering project by the San Antonio Express-News and the Denver Post’s coverage of the Colorado movie theater shooting.
The two platforms work a little differently. Dipity is a WYSIWYG (short for “what you see is what you get.”) Users insert links, images, text and video directly into the timeline. This video gives you a quick overview:
TimelineJS, meanwhile, is based on a Google Sheets template that allows users to drop in text, photos, videos, maps and more. Click here for the template and step-by-step instructions.
(Both Dipity and TimelineJS are also popular among educators. Here’s a piece from the Chronicle of Higher Education about TimelineJS. And here’s another about Dipity.)
UPDATE, June 18: Here’s another example of Timeline JS from CT News Junkie. Note how the editors designed a still image with a click button to work with the site’s narrow center column.