'A Closer Look at the Small World: Observing Microorganisms' at Seoul Sewer Science Museum is a one-time free class for elementary school pupils in grades 3–6. The official Seoul booking page lists Saturdays from October 10 to December 12, 2026, 14:00–16:00, with a maximum of 20 pupils per session. Activities cover the museum's permanent exhibition, wastewater treatment, the role of microorganisms in purification and observations through microscopes. Book first-come through Seoul Public Service Reservation. One account can register only one child; two siblings need separate guardian or child accounts. Check whether the booking is confirmed rather than waitlisted. Failure to appear without advance notice can cause a 60-day ban on future museum education reservations. The venue is Seoul Sewer Science Museum, 64 Jadongchasijang 3-gil, Seongdong-gu, inside the Jungnang Water Reclamation Center. The official directions describe about ten minutes on foot from Janghanpyeong Station (Line 5), Exit 8. For driving, navigate directly to the museum parking lot and use the entrance gate across from Seoul Upcycling Plaza. The listing states the first 30 parking minutes are free, then KRW 300 per ten minutes. Inquiries: 02-2211-2556. The official reservation notice states that photographs taken during the class may be used in the museum's publicity and publications. Guardians should review this notice before registering a child.