1 - A guy singing all the parts himself through the magic of recording technology - charming:
This is also a good place to point out that another term for a round is a simple canon. There are other types of canons where the original melody is not repeated exactly - can be a variation, or reversed, or at an interval, etc. But that's a bit complicated for our purposes.
2 - I love this version, though it's not sung as a round. 1970 reggae:
3 - And finally, in the original German, more or less, by a guy and girl who look like they are at a camp similar to Ajawah: