By killing multiple enemies in a row, you can get 100 - 200 - 400 - 500 - 800 - 1000 - 2000 - 4000 - 5000 - 8000 - 1UP - 1UP - 1UP ... (1UPs from the 11th enemy onwards) (source).
I know there are several places where you can do the glitch/turtle trick to get infinite 1UPs this way (e.g. a compilation of many such locations, 4-1, a very complicated way in 1-2).
However, without using this glitch/trick, where can one kill 11+ enemies in a row to get the 1UP this way?