Legend has it that when Emperor Charles IV decided to build Charles Bridge in 1357, he asked Czech villages to send eggs to Prague to mix into the mortar and make the foundations stronger. One overzealous village misunderstood and sent hard-boiled eggs. That's why, as the story goes, the bridge is so sturdy and has lasted so long.

Even a hard-boiled bridge needs periodic structural repairs, and one planned soon will likely challenge Prague at the height of the summer tourist crush — though City Hall seems eager to downplay to what extent.

The city is at odds with itself over a massive restoration of the span that could begin as early as next month. Jiří Toman, director of Prague City Hall's investment department, says if he has his way, the bridge would to be closed to

foot traffic during at least some of the repairs, which are expected to stretch over 16 months during the next two years.

"The bridge will not be shut down," counters Jiří Wolf, a spokesman for the mayor's office. He says that parts of the bridge will have limited access during construction.

Charles Bridge did sustain some structural damage during the 2002 floods.

The bulk of the work, expected to cost around 250 million Kč ($10.6 million), will involve repairing the internal structure of the body of the bridge to improve its resistance to water, restoring its pillars and repairing external stonework. In addition to the two years of intensive repairs, smaller repairs will continue for 10 years thereafter.

Prague's icon

Some 20 million tourists visit Prague each year, and almost all of them cross Charles Bridge at least once, often stopping to touch the plaque at the base of the statue of St. John of Nepomuk for good luck. Few tourists could imagine Prague without the bridge.

Not surprisingly, some in the tourist industry are concerned about how the bridge's closing, now just a possibility, would affect business.

"Charles Bridge is the most iconic monument in Prague," says Jaroslava Nováková, director of Pragotur, a section of the Prague Information Service. "Shutting down the bridge would be very unfortunate for tourism here."

Others are trying to put a braver face on the prospect.

Stanislav Voleman, president of the Tour Guides Association, says that for tour guides, shutting down Charles Bridge would just mean having to find a new route across to Malá Strana.

But what route would compare with the one that starts underneath the astronomical clock on Old Town Square; passes through the narrow, cobbled streets of Old Town, crosses Charles Bridge to Malá Strana and leads up Nerudova street to Prague Castle?

"All the main historical monuments run in a continuous line connected by Charles Bridge," says Roman Kotrč, a member of the Association of Charles Bridge Artists, a nonprofit organization.

"Severing that line would have a dreadful impact on tourism," he says. "It would take years for it to recover."

Kotrč recalls how after the 2002 floods, it took nearly two years for tourist traffic on the bridge to reach the same levels as before the floods. And he doesn't want to see such a slump in tourism again.

The outdoor studio

Reduced foot traffic on the bridge promises to be a big blow to the artists who treat the span like their studio, selling portraits and photographs, crafts and caricatures. There are also the musicians — the lone guitar player, the ensemble brass band — that rely on eager listeners.

"These people will be finished," Kotrč says. "Their art has been entirely focused on the bridge."

City Hall hasn't set an exact start date for the repairs yet. Media reports have said the work could begin next month, but Vladimír Křístek, vice president of the Czech Association of Building Engineers, says repairs are more likely to commence just before early summer.

In the meantime, hundreds of guides and artists will be holding their breath.

Work long planned

Projects for the bridge's renovation have been around for 10 years now but none have gone forward.

That's because the city lacked the money for the undertaking, and various city organizations couldn't agree on just what needed to be fixed on the bridge. One dispute has been whether to keep or redo the repairs the city carried out in the 1960s and 1970s.

According to Křístek, the biggest flaw of those repairs was that they involved installing low-quality insulation into the structure that allowed water to enter the body of the bridge more easily.

Jiří Witzany, rector emeritus at Czech Technical University, who was involved in past efforts to repair the bridge, says the city should spare no expense on a monument of such great historical importance.