If the 20th century saw the birth of international tourism, then the 21st century has seen the boom in ecotourism. In this edition of Bloomberg Green, we'll look at the fastest-growing part of the travel industry: sustainable holidays. First, we'll look at the example of Costa Rica, which was an early adopter of the 'eco' label. Then we'll speak with the CEO of Omio, a start-up aiming to become the Skyscanner of ground transport. Our reporters investigate the darker side of the industry, with a new conservation project in Kenya that is having detrimental effects on local people. And finally, ecotourism pioneer Megan Epler-Wood joins the program to discuss how to regulate the industry and stop greenwashing.