Talks on real heroes

Quite often society offers us false heroes, people who did nothing for us, but somehow they're very celebrated.
We celebrate generals, politicians, musicians, poets and actors.
I want to propose at steemit Weekly Hero commemoration.
But to me personally the most celebrated people should be those who made scientific and technological discoveries.
The most notable of these people do get recognized by Nobel prize, but I still think that they do not get enough credit that they deserve.
How do I measure the importance of the person for humanity ?
Simple. What would happen if we erase everything this person ever done, how would that affect life of humanity?
Lets take a great actor Marlon Brando

and compare him to this man Karl Landsteiner.

If we delete everything all the work Marlon ever done, we might lose some nice movies, but that's it.
But without work of Karl Landsteiner, hundreds or maybe thousands of people would die in hospitals every day, because blood transfer from one person to another would be almost impossible without his discovery of of blood groups.

Images source : Marlon Brando - Wikipedia
en.wikipedia.org

Karl Landsteiner - Biographical ...
nobelprize.org

What other heroes do you know of ?
Keep your comments and upvotes coming
Thank you..