You walked down the stairs. You tapped and entered the gate. You waited on the platform. You started watching rats racing below the tracks. You missed the sun, the air, and everything of the world above you. You wish you had known that the next train was 7 minutes away. So before going down, look up. The project is a clock system that communicates subway trains’ schedules with the public. The revolution of each clock corresponds to one subway line’s frequency. As a public-scale timepiece, the project hopes to question the city’s infrastructure system and change activities happening around it.