LOOK: The Mount Stephen Hotel's 21st-century makeover

One of Montreal's most iconic buildings reopened to the public on Tuesday as a slick 21st century luxury boutique hotel.

The Mount Stephen Hotel's front building is the former home of CPR boss Sir George Stephen, who had the home built as a private mansion in the 1880s, in what was then Montreal's Golden Square Mile. Decades later, it became a social club before closing in 2011.

In the years since, the building underwent extensive renovations, and an 11-story hotel rose behind it, with 90 rooms and an opulent penthouse suite, which starts at $6,500 per night.

The hotel's general manager Antoine Naoum says the new hotel has retained the historical elements with some 21st century changes.

"The house remains the way it was, improved after the restoration," he says, "and through the house, you get through the hotel to register and check in and access the rooms."

He also says the hotel is starting to fill up, taking reservations from Grand Prix tourists and those coming for the city's 375th birthday celebrations.

-CJAD 800's Kelly Albert contributed to this report.