The Kurgon Wonder was a temporal distortion located in the Kurgon system. It was created when the Temperon attempted to destroy the Knights of Velyshaa which were trying to capture it, causing them to be frozen in a single moment in time.
The people of the Kurgon system invited delegates from the Galactic Wonders Commission to examine the Kurgon Wonder on board the Edifice, hoping they would name it one of the Wonders of the Universe. However, the ship came too close to the Wonder and became enveloped in a time distortion, ageing everyone on board to death except for the Sixth Doctor, Ellie and Azimendah. Presumably, the Kurgon Wonder ceased to exist when the Temperon was freed. (AUDIO: The Sirens of Time)