Conversation so far:
When did the renovations take place?
The Merchandise Mart was modernized in the late 1950s and 1960s.
What did the renovations entail?
The Indian chiefs were removed and replaced with concrete plates in 1961.
How much did it cost?
After a 10-year, $100 million modernization in the late 1980s.

Question: Have there been any other recent renovations?
Self-contained rewrite: Besides the renovations in the 50's, have there been any other renovations to Merchandise Mart?