When an enormous town house just won't do

From the Times today:

Mayor Michael R. Bloomberg’s town house at 17 East 79th Street is the epitome of Upper East Side elegance: five stories of flawless Beaux-Arts limestone with 7,500 square feet of exquisite living space, all within steps of Central Park.

But for the mayor, it seems, the house has been a bit cramped.

Over the past two decades, in transactions that have gone all but unnoticed, Mr. Bloomberg has been buying up space in the building next door, knocking down walls and combining two entire floors along the way. He now owns four of the six apartments at 19 East 79th Street, a white 1880 neo-Grec co-op town house.