It started 10 years ago, there are now over 75 thousand hidden in towns and cities around the UK, millions across the world and they are a great way of getting children and adults alike out exercising in the fresh air.

What are they? Geocaches that’s what, hidden boxes containing trinkets, photographs and all manner of exciting things and finding them is one of the fastest growing outdoor pastimes in the world.

For the more extreme followers there are geocaches to be found in the Anatarctic, at the bottom of the Atlantic Ocean and even on the International Space Station, but for beginners it’s probably better to stay closer to home.

It’s so easy to participate, all you need to do is register at geocaching.com for a free Basic Membership. and follow the step-by-step instructions to locate geocaches in your area.

Pick the one you want to track down, enter its co-ordinates into a GPS device or download a GPS app to your phone and off you go.

When you find a geocache you can take one or more of the items inside but you must replace them with ‘treasures’ of your own for the next explorers to discover.

You can even make up and hide a geocache box of your own as long as it is on common land or you have landowner’s permission and you register the co-ordinates at geocaching.com

Such is the growing popularity of this pastime, that the BBC sent Mike Bushell into the countryside to find out just what the fuss is all about.

You can see how he got on in this clip