Free-riding, overexploitation and underinvestment are among the dangers of common ownership. With wildlife populations and biodiversity threatened across the globe, it is obvious that new and innovative methods of addressing this crisis are vital to the future of our planet. Ecotourism and payment for environmental services are on the rise. Could 'the market' be the answer? Or should 'the state' tame the free rider? After all, the creation of national parks in order to achieve conservation goals is also increasingly popular. How do societies deal with their commons?