Pictured on the left is "de Harmonica", a Dutch organ, usually found on the streets of Den Helder near Amsterdam. The full-size Dutch organ is quite large, with a highly decorated façade. Very few are still hand-turned, most being driven by small gas or petrol engines. These organs are designed to play to the public - gently serenading. Their pipework usually features an undulating pair of "bourdon" ranks, alternating with "violins".
By contrast, the "German" kind of street organ pictured on the right is usually very small and hand-turned, sometimes called "monkey organ". A few feature trumpets for dramatic effect in the music, but those are relatively rare. The one shown here is my own 32-keyless organ, playing in Stony Stratford High Street.
The four models of street organ I built from scratch are detailed here: