An unusual observation tower designed by OPEN Architecture has been completed in the eastern Chinese city of Yantai. “Sun Tower” is 50 meters high and has a curved shape and functions as a giant sundial tracking the change of seasons. As the architects explained, the northern edge of the building is oriented towards the midday sunlight during the equinoxes, while the entrance tunnel coincides with sunset at the winter solstice. In the center of the tower is a semi-open theater that faces the sunrise over Zhifu Island on the summer solstice. The inner shell of the tower faces the ocean, absorbing its sounds and amplifying them within the structure. The plaza features elliptical rings symbolizing planetary orbits. A water channel, on the other hand, carved into the stone pavement, marks the shadow of the building at certain hours of the equinoxes. One of the outer rings is a fountain dedicated to the 24 solar periods of the traditional Chinese calendar. At the top of the structure are a library and a viewing platform with a unique “Phenomena Space”. There, rainwater is collected in a special pool. There are also exhibition spaces with digital screens and projections