As a respect to the spirit of waters, Thais celebrate Loi Krathong festival.
In Thailand, Loi means “to float” while Krathong means “lotus-shaped receptacle”.
According to wikipedia.org;
Originally, the krathong was made of banana leaves or the layers of the trunk of a banana tree or a spider lily plant. A krathong contains food, betel nuts, flowers, joss sticks, candle and coins. Modern krathongs are more often made of bread or styrofoam. A bread krathong will disintegrate in a few a days and be eaten by fish and other animals. The traditional banana stalk krathongs are also biodegradable, but styrofoam krathongs are frowned on, since they are polluting and may take years to disappear. Regardless of the composition, a krathong will be decorated with elaborately-folded banana leaves, flowers, candles and incense sticks. A low value coin is sometimes included as an offering to the river spirits.
Since this doings has become one of Thais’ traditions, today this is becoming more modern with lots of fun and enjoyable events like floral parade, river boating contests and other recreations and sports.