Building a sand mountain or sand pagoda is a traditional custom observed during the Khmer New Year celebration in Cambodia. The sand mountain symbolizes the process of merit-making and also serves to honor the ancestors. This practice is rooted in Buddhist beliefs and is an important cultural tradition in Cambodia. 

The act of building a sand mountain is considered a form of charity and is believed to bring good luck, prosperity, and blessings for the upcoming year. It is also seen as a way to pay respect to the spirit of deceased ancestors and to make offerings to them. 

During Khmer New Year, people gather at pagodas to construct elaborate sand mountains decorated with flags, flowers, and other colorful ornaments. The sand mountain building process is a communal activity that involves people of all ages. 

Overall, the act of building a sand mountain during Khmer New Year is a meaningful and symbolic tradition that reflects the cultural values, spiritually, and community spirit of Cambodian people. 

Dethsovann002, CC BY-SA 4.0, via Wikimedia Commons