NEW YORK, Aug 6 ― One of the neat things about the 21st century mobile device is there can be a window into the past with apps like ‘Ken Burns’. It includes special remixed versions of the celebrated documentary makers’ videos.

Here, Kit Eaton reviews the three apps that will help you brush up on past events ranging from the Roman era to World War I. ― New York Times

Three apps that will help you brush up on past events ranging from the Roman era to World War I. ― NYT pic