The poem "The Brook" by Alfred Lord Tennyson describes the journey of a brook from its origins through the landscapes it flows through until it joins a larger river. The brook is portrayed as having a lively personality and shares observations of its surroundings as it travels, interacting with other elements of nature. It notes various features along its path like hills, towns, farms and other brooks or streams it encounters. The brook suggests that while individual people come and go, it will flow on forever, continuing its journey endlessly through time.