Video report by ITV Wales journalist Rob Shelley
Wales is marking the first ever 'Dark Skies Week', with the aim of encouraging people to look up at the stars and raise awareness about light pollution.
Dark Skies officer Dani Robertson says light pollution can have a 'catastrophic' effect on wildlife and human health.
She said: "Together, the National Parks and Area's of Outstanding Natural Beauty are using this week to show just how easy it can be to tackle the problem, in most cases it's as easy as the flick of a switch.
"Wales has the highest percentage of protected dark skies in the World but light pollution is damaging to nature, from insects to birds."
Dark Skies said Snowdonia National Park is the second area in Wales to be designated as an International Dark Sky Reserve.
The Brecon Beacons National Park was the first area in Wales to be awarded International Dark Sky status.
Dark Skies says there are just twelve of these reserves in the world, and that on a clear night you can see the Milky Way, all the major constellations, nebulas (bright clouds of gas and dust) and shooting stars.