Google has now made available Royal Air Force reconnaissance photos taken during the Second World War of 39 war-torn European cities.
The Google Earth mapping software has been uploaded with the wartime images of cities such as Berlin, Bordeaux, Hamburg, Cologne and Dresden. These images clearly display the destruction of allied bombing raids.
If one wants to see the most notable difference, he can see the historic photos of Warsaw from 1935 to the present day. The images show the heavy destruction caused to the Polish capital during the war, along with the city's infamous ghetto - the largest in Nazi-occupied Europe.
The viewers can easily forward go back in time, with the help of a slider bar at top of the screen.
To trace an example, users can track the post-war reconstruction of Warsaw's historic centre, a UNESCO World Heritage site.
"Many of us have heard stories, read books and watched films which show the many impacts of the Second World War across the world. By enabling people to compare then with now, in such a simple way, it reminds us all of the devastating impact of war on the people in those cities," said Google technologist Ed Parsons.
Even the primary and secondary school history students can take a lot of advantage from Google Earth tool, said Jan Odakowski, director of the Warsaw Rising museum.