One World Trade Center’s 94 stories took more than a decade to build. Watching the building’s incremental growth condensed into two minutes makes you appreciate just how massive a project it really is. The observation deck at the top of One World Trade Center officially opened on May 29, and to mark the occasion, EarthCam released this time-lapse video of One World Trade Center’s construction, from its start in October of 2004 through Memorial Day 2015.