The world's most spectacular and highest tides are a matter of daily routine in the Bay of Fundy, an inlet of sea that cuts about 170 miles into Canada's Atlantic coast between the provinces of Nova Scotia and New Brunswick.

Main reason for the gargantuan tides- which rise to 53 feet at some points-is the Bay's unusual funnel shape.

Not only do its shorelines converge sharply from mouth to head, but its bot­tom also slopes upward.

There is no outlet to the sea at the head of the Bay; thus when the tide sweeps in, its waters converge and build up as the Bay gets narrower.

At low tide, broad reddish mud flats lie bare beneath vertical cliffs that stand high and dry. Then twice each day the sea comes rushing in to fill this immense natural funnel, and the landscape is transformed into a seascape.