It wasn't the world's best-hidden marijuana plantation.

Berlin police say they were were called to a subway station Monday morning by a street cleaner who reported finding "numerous small plants that seemed suspicious to him."

Officers found 700 small cannabis plants growing among weeds on a traffic island outside the Kottbusser Tor station in the capital's Kreuzberg district. They pulled up the plants.

It wasn't immediately clear who planted the cannabis but police are investigating.