Since the region has an extended wet season, wooden or metal bridges would decompose far too fast; therefore, the Khasis developed a different eco-friendly alternative, making use of the roots of the Ficus elastica tree. The process of creating these root bridges is straightforward: a tree is planted on both sides of the river, the aerial roots are then carefully directed across the river, and the roots are entwined using the trunks of areca palm trees, bamboo, and stones as temporary scaffolding. Over 10–15 years, the aerial roots thicken naturally, establishing a self-sustaining, durable structure that requires very little maintenance. Some of these root bridges are believed to be over 500 years old. They have endured the most extreme weather events.