There are a plethora of quality talks and lectures available free via the internet. An obvious place to start would be https://www.ted.com/
The purpose of TED talks is to inform and educate global audiences in an accessible way. Scientists, researchers, technologists, business leaders, artists, designers and other world experts take the TED stage to present “Ideas Worth Spreading”: valuable new knowledge and innovative research in their fields. You can find talks on all sorts of subjects
