lightweight What is a bivy sack? Ultralight minimalism for overnight adventures What is a bivy sack? We look at the ins and outs of the ultra-light shelter that's a dream come true for minimalists in the outdoors Advnture NewsletterAll the latest inspiration, tips and guides to help you plan your next Advnture!Contact me with news and offers from other Future brandsReceive email from us on behalf of our trusted partners or sponsors MOST READ1Marathon final-place finisher’s video becomes inspirational internet sensation2Fjallraven Abisko Hike Trousers review: lightweight comfort for summer hikes and active travel3How did this Colorado peak just get demoted to the shortest 14er in the state?4"The bear probably had a pretty traumatic experience" – disturbing video shows people hauling cub out of tree for selfies5Friday 5: fell, mountain and ultra runner Nicky Spinks