The Rideau Convent Chapel is a centrepiece of the National Gallery of Canada. The chapel was built in 1887-88 as part of the Convent of Our Lady of the Sacred Heart, which stood on Rideau Street. That convent was demolished in the 1970s, but the chapel was saved by the efforts of heritage groups and various government levels, and relocated here. The Chapel is, as noted on the panel leading inside, "the only example of its kind in North America from this period to include a Tudor style fan vaulted ceiling", and as such was well worth saving. It is a beautiful and peaceful space, and periodically when I visit, such as was the case this time, it features an audio art installation. Janet Cardiff devised The Forty Part Motet, a reworking of a sixteenth century work by the English composer Thomas Tellis. Forty singers, recorded individually, are played back through the speakers arranged through the room. If you stand by one, the emphasis you hear is that single singer, which applies if you move forward to another one. If you stand in the midst of the room, the voices as a whole are as one. If you wait after it's over, for a few minutes you'll hear the sounds of people talking on the speakers, the collective sound of which is quite different from the singing. The effect is a sculpture of pure sound, and it is a joy to hear, particularly in such a splendid setting. You'll have to take my word for it- photography is allowed, but not video.