Living root bridges are a wonder of bioengineering. Found in the Khasi Hills of northeast India, these bridges are grown over decades and centuries by the local tribes using a Ficus elastica tree. As fantastical as they appear, these bridges face very real problems. Some have become tourist spots, and hundreds of people visit them during the rainy season when the forests are lush and inviting. Tourism, here as everywhere else, is a double-edged sword. It has undoubtedly brought in steady income for these villages: Locals make money from homestays and guiding, and the state government has begun to fund tourism development. But these bridges are built to withstand the weight of occasional local pedestrians, not hundreds of tourists scrambling for selfies. Some bridges have begun to show signs of damage. Besides this, in some places government funds have been used to build concrete stairs, walls, and ticket collection stands, often right next to these bridges, posing a long-term threat to their stability and sometimes blocking the roots. Fortunately, many locals are increasingly aware of these threats and are working toward developing a more sustainable model of tourism—for example, by considering a limit on the number of tourists.