BEILNGRIES, Germany (AP) _ The last section of a new canal filled slowly with water Friday, linking Europe from the North Sea to the Black Sea in a historic moment for international shipping.

A brass band played, and colorful balloons were released as about 1,000 people watched two excavators scoop away an earthen dam in the last dry stretch of the 106-mile, $4.7 billion Rhine-Main-Danube Canal.

A dusty, half-mile stretch of canal bed then filled with water from the Danube and from the Main, a tributary of the Rhine.

When the canal opens Sept. 25, freighters will be able to sail the breadth of Europe: from Rotterdam up the Rhine, east up the Main to the German city of Bamberg, through the canal, into the Danube at Kelheim, and on to the Black Sea.

A sign posted at the canal on Beilngries' outskirts spells out the waterway's geographic significance. One arrow points to the North Sea, 652 miles away, another to the Black Sea, 1,521 miles in the other direction.

Government and canal authorities hope the waterway will improve western access to eastern markets and give an economic boost to struggling east European nations three years after they broke with Communism.

But while government authorities call the canal one of the most important developments in navigation, environmentalists say it is a disaster.

Canal workers radically altered the countryside, scooping out huge swathes of earth and rerouting streams.

''It would have made more sense to invest the money in the railway system, rather than finance this nonsense project,'' said Hubert Weiger, a leader of the Bavarian branch of the German Federation For Environmental and Nature Protection.

Weiger, who fought to stop the project for two decades, said the canal's construction has damaged the area's natural ecology ''for all time.''

Charlemagne tried to connect the Rhine and Danube river basins in the year 793, setting crews to work on a canal not far from here. But mud slides stopped the emperor's legions, and he abandoned the project.

King Ludwig I of Bavaria built a modest canal linking a Danube tributary with one from the Main in 1845. But it was too narrow to handle large boats and succumbed because of competition from the railroads.

The Rhine-Main-Danube Canal, begun 30 years ago, is big enough to handle 2,000-ton freighters, lifting them over the Franconian Uplands through a system of mammoth locks.