I actually don’t know what these are called but if you want to have a closer look, in 3D, this particular one can be found just by the lighthouse in Gilleleje.
Edit: My girlfriend just helped me out with today’s picture. In Danish this iron basket is called a “vippefyr“. The English name is a “tipping lantern”and they were used as guides for ships out to sea in the 18th century and before. apparently they weren’t that effective and were later on replaced by conventional lighthouses:)