Wondering about the biggest residential deals of 2014? Just look up: The number of $1 million–plus condos sold in the metro area rose 15 percent from the previous year to 491, according to Midwest Real Estate Data—the highest level since 2007. By contrast, the volume of deals for single-family houses in that stratosphere rose just 1.2 percent and remains well below prerecession levels. Still, it was a manse—Groupon CEO Eric Lefkofsky’s record-setting Glencoe buy—that led all 2014 sales.

Lefkofsky (No. 42 on our “Power 100” list) wasted no time upgrading this 15,800-square-foot French Normandy–style mansion after buying it in August: He hired Studio Gang Architects at year-end to add a gym and spa. Previous occupant David Helfand, copresident of Sam Zell’s Equity Group Investments, demolished and rebuilt two-thirds of the four-acre lakefront estate after purchasing it in 2002.

The 14,260-square-foot top floor of Donald Trump’s Chicago tower (marked above), which languished on the market for two years at $32 million, finally sold in December to the person who offered the most cash: Sanjay Shah, founder and CEO of Vistex, a software company. Perched on the 89th floor, the highest occupied residence in the Western Hemisphere is just drywall and concrete, but Shah plans to spend $15 million finishing it. Decorators take heed.

Ken Griffin, Illinois’s richest person (and No. 12 on our “Power 100” list), went on a buying spree last summer, adding 46th- and 37th-floor units at the Waldorf Astoria to his portfolio within two weeks of each other. Neither was publicly listed, making specifics scarce—but Griffin must be creating one heck of a bi-level bachelor pad as he wades through his messy divorce from fellow hedge funder Anne.

Only on East Lake Shore Drive would a midfloor three-bedroom co-op fetch more than $7 million, or roughly $1,300 a square foot. Sellers Raymond Kedzior, CEO of LoDan Electronics, and his wife, Dana, renovated the property in the Marshall & Fox–designed building to give it a decadent Old World look.

The buyer of billionaire Nicholas Pritzker’s Georgian mansion quickly secured permits for renovating the nearly 8,000-square-foot Astor Street sensation, which already includes seven bedrooms, five full bathrooms, four fireplaces, and separate staff quarters. Downton Abbey, anyone?