As the Sochi Winter Games approach — now only 100 days away — questions are being raised about what it’s costing to put it on: an estimated $51 billion, according to recent reports.

The 2010 Winter Games in Vancouver, by contrast, cost a more modest $7 billion. And as the CBC's Kirk Williams explains, most local observers now say that the bang was worth the buck, with an infrastructure legacy — from housing to transit — that will live on for decades.

With files from the CBC's Kirk Williams