Have a stroll around the older parts of Vancouver – specifically in and around the periphery of the Downtown Eastside – and it likely won’t take long for you to spot the little 3″ purple glass squares embedded in the oldest sections of sidewalk. These are known as vault lights or sidewalk prisms.
They were typically installed in the early 20th century before the common advent of civic electricity services. Their purpose was to naturally illuminate the basements of the businesses they fronted so that open flame wasn’t required (thereby reducing the risk of fire – a real anxiety in Vancouver after the Great Fire of 1886). The easiest place to behold their full effect (with a drink) is in the underground bar at Calabash. The pictures above were taken way back when the Caribbean-themed joint was under construction in 2010.
True story: the originals were clear, but the glass’ high manganese content gave them a purplish hue over time.