Conversation so far:
When did the renovations of Merchandise Mart take place
The Merchandise Mart was modernized in the late 1950s and 1960s.
What did the renovations of Merchandise Mart entail?
In 1962, a Merchandise Mart entrance canopy was constructed over the south for vehicle use.
How much did the renovations of Merchandise Mart cost?
A 10-year, $100 million Merchandise Mart modernization in the late 1980s included public utility upgrades.
Have there been any other recent renovations at Merchandise Mart?
Beyer Blinder Belle's commission in 1989 was to create additional perimeter entrances and restore the display windows, main entrance and lobby of Merchandise Mart
What kind of expansions have been done at Merchandise Mart?
On the south facade, the drive-through canopy was removed and two smaller doorways aside the main entrance were added to Merchandise Mart
Are there any interesting aspects of this Merchandise Mart article?
Display windows, painted over during the earlier modernization campaign, were restored with clear glass to showcase merchant's wares at Merchandise Mart
Who pays for all of the expensive renovations at Merchandise Mart?
Vornado Realty Trust paid for the Merchandise mart renovations
Who owns the building Merchandise Mart
In 1998, Merchandise Mart was acquired by Vornado for $450 million cash and a $100 million-plus stake in Vornado.

Question: How long did the renovations take?
Self-contained rewrite: How long did the renovations of Merchandise Mart take?