Step inside the World Trade Centre Montréal and you'll find a chunk of the Berlin Wall, an eighteenth-century French fountain, and a stretch of the city's colonial defensive walls, all tucked beneath an enormous glassed-in atrium. It's the strangest sort of skyscraper: one that lies on its side.

Inaugurated in 1992, this 'horizontal skyscraper' occupies a full city block where Old Montréal meets the Quartier International. Rather than demolish the historic buildings on Fortifications Lane, the architects swallowed them whole, encasing centuries of stonework in glass. The complex connects to the Underground City, Montreal's 35-kilometre pedestrian network that lets locals escape winter without stepping outside.

VoiceMap's self-guided audio tours walk you through the atrium itself, pointing out the Berlin Wall fragment donated in 1992 and tracing how the building turned a colonial fortification into a centrepiece of urban renewal.