Climbing frame or anti-terror device?
Concrete anti-terror blocks - also known internationally as Jersey barriers or K-rails - are an increasingly common sight around the world following attacks using vehicles as weapons in locations such as London, Barcelona and Nice.
One "urban gardener" in Copenhagen has decided to turn the ones in his city into a green alternative that includes benches, plants, bike racks and even a children's climbing wall.
BBC News followed Mads Boserup Lauritsen as he set about modifying a set of the blocks.
Video journalist: Cameron Robertson
26 Oct 2017