Take your pick of what you think is most important:
the pyramids were and still is the most important invention in ancient Egyptian time because, the pyramids were made for the kings and pharaoh and in Egyptian times they were the most important people in Egypt.
Probably the most important that happened in 1450 was the invention of the first movable printing press. Johann Gutenberg made it work for the first time.
The invention of the Firearm
It was the irrigation system.
A steam, or atmospheric, engine.
It lead to ideas being spread
laptop portability is the most important invention
the most important invention was the plow
Europe first single currency
While GPS is helpful it is not the most important invention of all time. Some would say computers are the most important invention of all time. However what powers both of these things? Electricity seems to be the most important invention of all time.
The most important invention in world war 2 was the atomic bomb.
The Ubaid are considered the first agents of civilization in the region.
The most important invention of the Sumerian's was Irrigation. Irrigation is how the Sumerian's led their water through pipes, etc.
The most important invention was gunpowder
THE corsett?
The Wheel
The invention of the Firearm