A riverboat is a boat specially designed to travel on rivers rather than oceans. Rivers present unique challenges: they're shallower than seas, filled with sandbars and hidden obstacles, and their currents can shift unpredictably. So riverboats are built with flat bottoms that don't sink deep into the water, allowing them to navigate in places where ocean-going ships would scrape against the bottom and get stuck.

The most famous riverboats are the grand paddlewheelers that traveled American rivers like the Mississippi and Ohio in the 1800s. These magnificent vessels had enormous paddle wheels on their sides or stern that churned through the water, pushing the boat forward. They carried passengers, cargo, and mail between river towns, and many featured elegant cabins, dining rooms, and even entertainment. Mark Twain worked as a riverboat pilot before becoming a famous author, and he wrote about the skill required to read a river's surface and navigate safely.

Today, riverboats still operate around the world. Some carry tourists on scenic cruises, while others transport cargo on major rivers like the Amazon, the Nile, and the Yangtze. The term can also refer to smaller fishing boats or flat-bottomed johnboats that people use for recreation on calm rivers and lakes.