Learn vs learn about

[arzgol]

Should the verb ''learn'' come with the preposition ''about'' or we can omit it in the below sentence?

It is essential for the younger generation to learn about the brutal aspects of Nazi Germany in the massacre milions of people in the Second World War.

I appreciate taking your time to answer my question.

 

[5jj]

Should the verb ''learn'' come with the preposition ''about'' or we can omit it in the below sentence?

It is essential for the younger generation to learn about the brutal aspects of Nazi Germany in the massacre of milions of people in the Second World War.

We cannot omit it in that sentence.

If I learn the list of English modals, I memorise the list.
If I learn about English modals, I discover how they are used.

In some parts of the world, regrettably, police officers learn methods of torture, so that they can use such methods when they interrogate suspects.

In the civilised parts of the world, we are horrified when we learn about these methods.