It's the first activity on the 50 things to do before you're 11 ¾ challenge and if you're heading to the woods, then you should be able to find a tree or two to climb. You'll need one with thick branches that will be strong enough to hold your weight.
Choose a flat, dry spot and start building your den. You can make it out of any materials, but branches, twigs and leaves are a good place to start. Then you'll just need a keep out sign for when you're done!
No.12 make a trail with sticks
Pick up sticks or fallen leaves and lay a trail for your family to follow. Please don’t pick sticks from living plants or trees though.
No.13 make a mud pie
Put on your wellies and find a muddy spot. Stones, leaves and twigs are great for decorating, but remember, a mud pie never tastes as good as it looks.
No.18 Create some wild art
Woods have pretty much everything you could need to create your very own piece of wild art. You could use leaves, sticks, acorns, mud, grasses, conkers, feathers or anything else you find to make some art.
No.22 explore inside a tree
Trees with huge trunks sometime have huge holes, making them great for exploring. We even have hollow trees at a few of our places, perfect for adventurers. Watch out for insects and wildlife though - lots of things like to live in the holes of trees, so you might end up sharing.
No.24 go on a walk barefoot
Barefoot walking gives your feet all sorts of sensations as you feel the different types of ground, from sand to earth and grass or moss. Close your eyes and see if you can work out what you're standing on - but don't keep them closed while you're walking!
No.31 hunt for bugs
Your garden is a great place to look for all sorts of bugs - try searching under rocks and stones, or bits of wood, in the soil or the grass. Lots of bugs have homes outside so you're bound to find something.
No.33 Catch a falling leaf
It sounds like one of the easier challenges, but catching a falling leaf can be tricky - all you need is a little gust of wind and off your leaf goes, spiralling away from your hand. If you can do it though you'll have ticked off another of the activities on the list!
No.36 make a home for a wild animal
All sorts of animals need homes, so why not try making a bug hotel, a house for a hedgehog, a motel for a mouse or even a palace for a fox. Think about the creature you're making a home for - does it need to be warm, light, dry, dark, cold, or wet?
Even bold adventurers don't need to go too far from home to tick off challenges from the 50 things activity list. Here are our top ten ideas for activities that you can do in your own back garden, nearest park or outdoor green space.