Linda Pitkin / 2020VISION / Tube worms (Bispira volutacornis) living between rocks covered in Crustose coralline (Corallinaceae) and red algae (Rhodophyceae), Lundy Island Marine Conservation Zone, Devon, England, UK, May.

Orsolya Haarberg / Calyx tube of the Northern catchfly (Silene uralensis apetala) Abisko National Park, Sweden, July

Alex Mustard / Yellow tube sponge (Aplysina fistularis) top view of tubes with water swirling around them, Grand Cayman, Cayman Islands, British West Indies, Caribbean Sea.

Alex Mustard / A diver exploring a coral reef with formation of brown tube sponges (Agelas conifera) red rope sponges (Amphimedon compressa) and deepwater sea fans (Iciligorgia nodulifera) East End, Grand Cayman, Ca...

Alex Mustard / Secretary blenny (Acanthemblemaria maria) making a home in a deserved worm tube of a great star coral (Montastraea cavernosa), East End, Grand Cayman, Cayman Islands, British West Indies, Caribbean Se...

Alex Mustard / 2020VISION / Tompot blenny (Parablennius gattorugine) in bright summer mating colours, peering out from his home in a discarded tube, where he was guarding his eggs (not visible in this photo), Swanage Pier, Dorse...

Jeff Rotman / Yellow tube sponge (Aplysina fistularis) Red Sea, Egypt

Juergen Freund / Orange cup coral (Tubastrea faulkneri) with polyps open, Batangas, Philippines.

Juergen Freund / Orange cup coral (Tubastrea faulkneri) detail of mouth and tentacles, Batangas, Philippines.

Juergen Freund / Brown tube sponge (Agelas tubulata) in the reef, North Sulawesi, Indonesia.

Juergen Freund / Researchers Guido and Katja Westhoff work in a mobile lab in the bush. To handle the deadly Common death adder (Acanthophis antarcticus) Guido puts the head and upper portion of the snake in a plastic...

Florian Möllers / House sparrow (Passer domesticus) breeding in the cannon tube of a tank at the Russian War Monument, Unter den Linden, Berlin, Germany, June 2007