Time lapse Videos - saved as MP3 for powerpoint presentation

I require 20 different time lapse youtube videos saved as MP3, approximately 20 seconds for each video. I want no writing or information on the video. Each video will be played on a separate slide for a powerpoint presentation. Some ideas are: lightening storm on the Effile Tower, Volcano erupting, building of Sydney Harbour bridge, flower growing, butterfly emerging from cocoon, earth from space, tornado, lightening storm, northern lights etc