Same with photo's now, caution, we put them into PB or similar but hardly ever print them out, so there won't be many for future generations.

 Surely its only been the last 120 years that we have had photos at all ?

 Thats about 4 generations ago ?

 there have been hundreds nay thousands of generations in Human development

If you do spend time looking a few generations back at photos and letters , a few minutes is probably how future generations will look at you , indeed in 100 years , who bothers ?

Like wise

 170 years ago , Britain was so strong , that she sent a warship to China , and it wiped out the entire Chinese Navy in afternoon !

 http://en.wikipedia.org/wiki/First_Opium_War

 Do you think Britian could do that now ? has our power declined ?

 Will another 170 years  change anything ? will Britain stop declining ? will other countries stop developing ?