Google Earth History After the Google Earth Software was published on the Internet and became a striking success, I noticed that this software made many basic features available, which were necessary for an idea I have carried around with me for a couple of years. Actually, the idea is connected to a question that many of us have asked ourselves: You are walking on 5th Avenue in New York and wondering how this street looked 20, 50 or 100 years ago. Of course you can look up photos in relevant books or magazines and obtain a certain impression of how life was at a certain point in time in this place. But wouldn’t it be great to be able to transform this impression and create a detailed picture; to be able to literally see more and truly visualize your impression? In addition to the one or two photos which can be found in old magazines or in history books, there must be other historical documentation, which can assist in creating the picture. Surely, you can look at movie documentation, but mostly the specific place that you are interested in, is only briefly shown – or not shown at all. So let us stick with the example of 5th Avenue, New York. A place which has existed for more almost 100 years in its current form; which means something to almost every person in the western world; and which has been visited by a vast number of people at least once. As tourists like to do, they photograph the places they visit to show family and friends, where they have been. It is safe to assume that 5th Avenue is one of the places on Earth, which is most incessantly photographed by a large number of people. What a pity that all these photos are brought back to their owners’ home countries, and thus spread all over the world. The final resting place of these photos is mostly a photo album, a dusty box in the attic, or - in this digital age – a hard disk or a CD-Rom. The sum of all these photos of 5th Avenue would probably form a breathtaking historical view of this street: millions of pictures documenting all small and large changes throughout decades, pictures of well-known people visiting the avenue, events which happened here, the rise and the deterioration of different buildings. This collection of documents resembles traveling back in time in a way, that nobody has ever done before. If the owners of all photos would run their pictures through a scanner or make already digitalized photos available to the general public, you would quickly obtain an unusual diversity of photo documents. Especially, you would gain a multitude of different pictures of well-known places like the implied 5th Avenue. Once more we’ll look at an example: assuming I have a color photo from September 1994 taken on the corner of 5th Avenue and 23rd Street in New York City on which you can see e.g. the Empire State Building. I scan the photo into my computer and use the appropriate import function from Google Earth. Thus, the scan of my photograph is saved on a Google server. With the 3-D view of my Google Earth program I can now head for the corner of 5th Avenue and 23rd Street. On the exact location, where I took my picture in the real world in 1994, I now save the photo in the program’s virtual space. If many other Google Earth users would do the same thing with their photos, we would slowly have a collection of pictures from 5th Avenue. All other users now have the possibility of viewing all saved photos. So, if another user saves a photo of 5th Avenue and 28th Street, all I will have to do is to virtually move five streets north and position myself behind the digitally stored picture in order to view it. Of course, we would soon have chaotic conditions if enough people upload their pictures of 5th Avenue to the Google server: One has a photo from December 1980, another person a photo from June 1982, the third a very recent photo from 2006. All these photos will be saved geographically correct in the Google Earth program, but content-wise they will not fit together at all in such a chronologically un-sorted manner. Therefore, the program Google Earth would have to contain a new function: the depiction of the fourth dimension, time. In short, before you save a picture from June 1971 in the correct virtual place in Google Earth, you will also have to set the correct time, i.e. June 1971. In reverse, for the viewer this means that he will have to select from which time in history, he wants to see photos of the chosen 3-D surroundings, before he views the pictures in the Google Earth 3-D world. So, what is it all for? Just as Wikipedia to this day has proven very impressively, that the accumulation of individual persons’ knowledge on the Internet in sum constitutes a high value of total knowledge, so this collection would form a library of historical documents. Again we will remain with the 5th Avenue example: with a sufficiently large collection of photos the viewer has the option of looking at the street from different perspectives AND from different points in time, which may even be many years apart. History has probably never bee so easy to observe. In the end maybe he sees himself taking his photo in September 1994 while somebody other shot a photo with me in the picture. Strange, isn´t it?