Location in time

http://www.infoplease.com/
On this date in history.... U.S. and world events, including sports, entertainment and science, from any year between 1900 and now. Click in the lower right of the lavender rectangle to view a calendar.

Look in the middle of the screen for
Year-by-Year Chronology: 1900–2008 
Enter the year you want and click on “go”

Time and date.com
Time clocks for around the world.  Calendars for any year.
Calculate duration between two dates.
Countdown to any date
Sunrise and sunset calculator
Time Zone converter

Time Zone map, Shows Greenwich mean time around the world.

http://users.erols.com/mwhite28/timelin2.htm
Timeline of 20^th Century History.  Quick overview of other significant events during your time period of interest.

Using flashbacks in your prose

Tips on using flashbacks by Camy Tang.