Mark Twain once called the Leaning Tower of Pisa "the strangest structure the world has any knowledge of." For more than a decade, experts from across the globe have been working to keep it that way.

The leaning tower and the Duomo, both of creamy marble, attest to Pisa's once powerful standing.

Officials closed the tower in 1990, when it leaned by a dangerous 13 feet off the perpendicular. In June, Italian and foreign engineers completed an 11-year, million restoration project to reduce its tilt by 16 inches.

"It will take another 300 years for the lean to get back to where it was in 1990," predicts John Burland, an engineering professor at London's Imperial College.

Last month, Pisans toasted the reopening of their beloved landmark with a celebration.

Gone are the support suspenders and gaudy steel rings that strangled the tower for much of the last decade. Still, visitors must wait until November to make the dizzying climb to the top, as experts continue to study the structure's stability. In the past, tourist groups filled the eight-story tower's staircase. This time around, however, only 30 individuals will be allowed inside at a time.

Construction on the famed bell tower began in 1173, when Pisa was a powerful maritime republic. But it was a monument built on shifting soil. The tower's south side began to sink before workers completed its third level.

The tower was finished in 1360, still stubbornly tilting -- and all the more famous for it. Galileo is said to have conducted his revolutionary experiments with falling objects from the off-kilter belfry.

As one of Europe's oldest university towns, Pisa has a strong intellectual tradition. The cafe-lined Borgo Stretto and the Piazza dei Cavalieri often teem with students.

Pisa is on the coast of Tuscany, a region famed for its food, wine and beautiful hill towns. Many people visit Pisa as a day trip from Florence, about an hour away by train.

(Agencies)