Visiting Bath, England regularly over the last two years, I've been watching the progress of the Nicholas Grimshaw-designed Bath Spa Project. In March 2002, the shell and superstructure phase of its construction was completed.

The city of Bath is a World Heritage site, and the prestigious Bath Spa Project aims to revitalize the Spa quarter of the Georgian city, whose natural, thermal waters have fallen into disuse since they were last used for leisure and medicinal purposes 20 years ago.

An abandoned swimming pool in Beau Street has been replaced with the only new building in the complex; a contemporary structure of glass and stone offering bathing, gymnasium, and massage facilities. This building is essentially a cube within a cube.

Within a glazed envelope, spa facilities are contained in a three-story, free-standing, cube of golden bath stone, the dimensions of which relate directly to the plan of the adjacent Hot Bath building designed by John Wood in 1775. The relationship of the building's nonrectilinear glass "skin" to its geometric inner cube is reminiscent of Decimus Burton's subsequent enclosure of Wood's Hot Bath with curved screen walls.

The free-form pool, illuminated by daylight filtering through the external glazed facade, features columns that support the internal cube. Glass lenses provide views out of the building, while safeguarding the privacy of bathers reclining on benches around the four circular glass steam rooms.

Work on the project is due for completion later this year.