Loi Krathong (known locally as Yi Peng), held on the full moon of the 12th month of the traditional Thai lunar calendar. In the Western calendar this usually falls in November. Every year thousands of people assemble floating banana-leaf containers (krathong) decorated with flowers and candles and deposit them on the waterways of the city in worship of the Goddess of Water. Lanna-style sky lanterns (khom fai or kom loi), which are hot-air balloons made of paper, are launched into the air. These sky lanterns are believed to help rid the locals of troubles and are also used to decorate houses and streets.