A chimney sweep is a person whose job is cleaning the inside of chimneys. Before modern heating systems, most homes burned wood or coal in fireplaces for warmth and cooking. As the smoke rose up through the chimney, it left behind sticky black soot and a substance called creosote that could build up over time. If a chimney got too clogged, smoke couldn't escape properly, and the creosote could even catch fire. That's where chimney sweeps came in: they climbed up inside chimneys or lowered brushes down from the roof to scrub away the dangerous buildup.

During the 1700s and 1800s in England, many chimney sweeps were young children. Their small size let them squeeze into narrow chimneys, but the work was miserable and dangerous. They breathed in toxic soot, got burned, and often became seriously ill. This cruel practice eventually became illegal after people recognized how wrong it was.

Today, chimney sweeps still exist, though they use modern tools like powerful vacuum cleaners and special brushes. They work on homes that have fireplaces or wood-burning stoves. You can recognize a traditional chimney sweep by their distinctive outfit: black clothes covered in soot and sometimes a tall top hat, an image famously shown in the movie Mary Poppins.