Glow­worms, glow­worms, as far as the eye can see. Okay, not lit­er­al­ly, but the Wait­o­mo Cave sys­tem on New Zealand’s North Island is famous for the flu­o­res­cent fau­na that light up the walls, giv­ing it the not-par­tic­u­lar­­ly-cre­a­tive but com­plete­ly accept­able ‘Glow­worm Caves’ nick­name. They are more acces­si­ble than most caves on this list, with raft­ing and adven­ture tours avail­able to those look­ing for some­thing a lit­tle more adren­a­­line-heavy.