Simplify the following text for a Grade 10 native English-speaking person.
Original: Lager Sylt was a Nazi concentration camp on Alderney in the British Crown Dependency , the Channel Islands , in operation between March 1943 and June 1944 .
Simplified: Lager Sylt was a Nazi concentration camp on Alderney in the Channel Islands , in operation between March 1943 and June 1944 .