I would like to know if there are any 'accessible' books to understand measure theory. I came across videos of Jay Cummings on YouTube channel 'The Bright Side of Mathematics' (if anyone knows that) and fould almost everything I was looking for, except for the fact that I couldn't truly get through the first videos until sigma algebras are introduced. I cannot picture in my mind any understandable example, what basics I am missing not to be able to understand them? I have been through some abstract algebra but that didn't help, except for the formalism.