Stamps - Technology

Over the years my grandmother bought a ton of stamp sets for the kids who collected them.  But over time the kids stopped collecting the stamps but she kept on buying them.  Some of the sets have made their way to me, one of which dealt with technological advances.

It's cool to see what things various countries have commemorated via stamps.  This set had stamps from Australia, Indonesia, Antigua, the Republic of Congo, Belgium, Rwanda, Germany, etc.