The Octagonal Tower was completed in 1925 and is the spiritual stronghold of Tamsui High School, representing the architecture of the Mackay era. The building, originally named "The Faith, Hope, Love Tower," was designed by Mr. K. Doawie, a math teacher and missionary, who referenced famous schools in England and America. The tower not only combines Eastern and Western styles but also incorporates local Taiwanese architectural elements. The layout follows the traditional three-in-one courtyard design. The 60-foot main tower is flanked by two-story buildings, with the classrooms on either side gradually decreasing in height. The front classroom is topped with a wing tower, featuring a balcony at the front and verandas on both wings. The three towers encircle a lush front yard, with a central path leading to the main entrance through a coconut grove. The main entrance features a carved granite lintel with a pair of stone drums and lanterns, showcasing Chinese aesthetics. Above the main entrance, Wu Tingfang inscribed the school motto "Faith, Hope, Love" in seal and clerical scripts. The original sign read "Tamsui Middle School" in clerical script. During the Japanese administration, the school name was changed to "Private Tamsui High School," and two rows of Alexander palms were planted along the entrance path. A second floor was added to the east wing. After the merger of the boys' and girls' schools in 1956, a second floor was added to the west wing, resulting in the current appearance. This charming building not only fosters a refined academic atmosphere at Tamsui High School, providing an inspiring environment for cultivating humanistic qualities, but it has also become a popular romantic filming location for movies, TV shows, and advertisements.