The Kathmandu Valley is defined by its ancient river systems, which hold deep religious and cultural significance.
* **Bishnumati River:** Flowing near the Chhauni museum district and Swayambhunath, this river has historically been central to local agriculture and religious rituals. * **Bagmati River:** The most sacred river in the valley, passing by the holy Pashupatinath Temple. Though both rivers face modern ecological challenges, massive community-led cleanup campaigns are ongoing to restore their historical purity.