A glass box-like punctuation point to its original palazzo-style museum, the new Renzo Piano-designed addition of the Isabella Stewart Gardner Museum opened January 19 to critical acclaim, with accolades for the functionality of the architecture itself.

The Boston Globe notes, "...its sloping glass walls and copper-sheathed cubes lend it the air of a cutting-edge science laboratory that wandered across the Charles River from the MIT campus," even while the Pritzker Prize-winning architect "kept the integrity of Gardner’s personal vision intact" with purpose-built spaces for enjoying live music and viewing contemporary art.

Mrs. Gardner built her Venetian palace-like art repository in 1903 to house her renowned collection and it now hosts a modern extension with many amenities such as apartments for resident artists, offices, conservation labs, a classroom, and a temporary exhibition space.

A new 296-seat concert hall will help open up viewing of Mrs. Gardner's Tapestry Room, which had been used for decades for concerts and lectures, and is filled with 16th-century Flemish tapestries, Italian furniture, and a stone fireplace.

Cafe G in the light-filled extension allows the cramped gift shop and cafe added in the 1970s to return to being an exhibition space of Asian art.

Traffic flow into the original museum will also ease up with a fresh entryway. Visitors who once entered through a small foyer will no longer clog up the view to John Singer Sargent's masterpiece "El Jaleo."

As many as 250,000 visitors are expected this year compared to a few thousand in Mrs. Gardner's day.

The near-2,500 piece collection is still on view according to Mrs. Gardner's vision, except for some missing mastepieces, including works by Vermeer and Rembrandt that were stolen in 1990 in the world's biggest art heist.

Medieval and Renaissance artifacts, European decorative arts, Asian and Islamic objects, and paintings by Titian, Rembrandt, Velazquez, and Manet mix with American paintings by artists who Mrs. Gardner (1840-1924) championed during their lifetimes, such as Sargent and James McNeill Whistler, and lesser knowns like Dodge Macknight.

Mrs. Gardner's artist-friends, along with art historian Bernard Berenson, helped form her world-class collection, while dancers and musicians of her day often performed at her museum or her more intimate salons, which makes the new concert hall seem most appropriate to her vision.

Controversy swirled around the razing of a 1907 carriage house and a 1930s annex to make room for the Piano-designed building, which is set back 50 feet from the original.

At least one visitor to the new addition was expecting a more robust temporary exhibition space, saying the current display contained only "...huge abstract paintings, a dress hanging on a hanger, a metal box filled with rusty nails, and a drum with bobbypins on top." Former Gardner artists-in-residence are exhibiting.

The new wing delivers needed functionality as a lobby, music venue, gathering space, eating area, learning center, and administrative space, so that the growing number of visitors can focus on Mrs. Gardner's assemblage of breathtaking art once inside the palace.