Cross Blackfriars Bridge at twilight and think Dementors drifting above the Thames

https://louisbtcd035.fotosdefrases.com/first-timer-s-guide-to-the-harry-potter-experience-london-tickets-and-transport

Cross Blackfriars Bridge at twilight and assume Dementors drifting above the Thames, as town lighting flicker like lumos inside the fog.