You could swim in the pools of sorrowful tears that fell from Parisian eyes that night.
The cries of mercy, the prayers to any supernatural form that would hear them, the anguish on the hearts of innocents suffering destruction, the darkness of hatred covering the eyes of the assailants, and the sadness of the City of Lights pouring through the streets.
With but a swift flush, the teary canals could cleanse the city of it's flaming tortures. The nations of the world, aching in sadness, unable to come to aid.
The tears they cried, and still cry, are not forgotten.