A tidal bore is a natural phenomenon that occurs in some rivers when a rising tide pushes seawater upstream against the current. This creates a sudden and strong surge of water, often forming a wave that travels up the river. Tidal bores can vary in size and intensity, depending on the geography of the river and the strength of the tide. One of the most famous examples of a tidal bore is found in the Severn River in the United Kingdom, where the bore can reach heights of over 2 meters. Tidal bores are also observed in other locations, such as the Qiantang River in China, attracting both scientists and tourists who come to witness this unique natural event.