Stupas in Sri Lanka are like big, tall, round buildings that people go to visit and pray at. They are also called dagobas. Stupas are really important to people who follow Buddhism, which is a religion that lots of people in Sri Lanka practice.
The stupas are usually made of bricks and sometimes covered in white plaster or stone. They have a pointy top called a finial, which is sort of like a fancy decoration that makes the stupa look nice. The inside of the stupa is usually empty, but sometimes there might be statues or relics of important Buddhist leaders or teachers.
When people come to visit the stupas, they usually walk around them in a circle, spinning prayer wheels or reciting prayers. There are also special ceremonies that happen at the stupas, like pouring water or offering flowers. People believe that visiting the stupas can bring them good luck or help them achieve inner peace.
There are lots of stupas all over Sri Lanka, but the most famous one is called the Ruwanwelisaya Stupa. It is really big and old and has been around for over 2,000 years! Lots of people still visit it to this day to pray and learn about Buddhism.