https://citychallenge.org/2026-10-211.0 https://citychallenge.org/rules2026-10-210.4 https://citychallenge.org/facts2026-10-210.8 https://citychallenge.org/partner2026-10-210.3 https://citychallenge.org/c/7-day-city-streak2026-10-210.6 https://citychallenge.org/c/hometown-landmark2026-10-210.6 https://citychallenge.org/c/city-nickname-quiz2026-10-210.6