PETRA

BACK in the 1960s, Israeli authorities outlawed a romantic ballad entitled "The Red Rock" to discourage adventurers from illegally crossing Israel's border with Jordan to visit the ancient city of Petra.

Those Israelis who touched the red sandstone of Petra became heroes and part of a secret, elite club that was talked about only in hushed tones.

Some were shot and killed, or injured, by Bedouins guarding the narrow, 600-foot-deep cleft that presents the most viable approach to the ancient ruined city. At most, Petra club members were counted in dozens or scores.

But today, since the signing of the peace accord between Israel and Jordan in October 1994, tens of thousands of Israelis have poured over the Jordan River by the busload to visit the land that was off-limits for so long.

The vast majority have visited since the beginning of this year, when the Jordanians increased the quota of Israeli tourists. According to the agreement between the two countries, Israelis may travel only with organized tours. Plans are under way to allow private Israeli vehicles to cross the borders.

The sudden influx has left the Jordanians in a state of shock.

"People have been told for so many years how bad the Israelis are," says Mekhled al-Zyoudey, author of the play "Madrid, Washington and Back," which spoofs the Middle East peace talks. "Ordinary Jordanians had virtually no say at all in the sudden peace with Israel. Now they are expected to change their attitudes to Israelis overnight," he says.

Another play that has attracted large audiences in Amman, entitled "Hi Citizen," is a fairly barbed send-up of Israeli tourists who are negatively stereotyped in the Arab world.

"For me, Israelis are just like anyone else. I have them as clients and the preconceptions have fallen away," says Jaffer Amer, who takes small groups to Petra and other places of interest. "But the average people have just not been prepared for the huge avalanche of Israeli tourists," he says.

Jordanians' attitudes are gradually changing, and resistance to Israeli tourists is giving way to curiosity born of an awareness that business is business.

When this reporter returned from Petra to Amman on the historic King's Highway earlier this year, he was stopped by a curious Jordanian shopkeeper in the town of Kerak.

"Is he Jewish?" the shopkeeper asked my Jordanian guide.

"No," he replied. Why did he want to know? "Oh. If he were Jewish, I wanted to extend a special welcome," the merchant said.

Not only Israeli tourists have poured into Jordan to visit Petra since the peace accord with Israel was signed last fall.

AT least 50,000 tourists from other countries have flooded across Jordan's land borders; tens of thousands more have flown in.

"Nothing has really changed since the peace, but foreigners believe it is safer now to visit Jordan and have been arriving in large numbers," Mr. Amer says.

Petra, situated about 150 miles south of Amman, is one of the most spectacular sites in the Middle East, and the vast majority of visitors to Jordan are heading for the ancient capital of the Nabateans, who dominated the area in pre-Roman times. (Moviegoers got a tour of Petra's spectacular scenery in climactic scenes from "Indiana Jones and the Last Crusade" in 1989.)

During the rule of the Roman Emperor Pompey, who conquered Syria and Palestine in 63 BC, Nabatean King Aretas III struck a deal with the Roman forces to remain independent.

But Rome exerted a powerful cultural influence that is reflected in the Roman architecture of Petra.

Nothing can prepare one for the thrill of the first glimpse of the rose-red city - complete with Roman columns and urns - hewn out of the towering sandstone cliffs.

The first view of Petra conjures up the excitement that Swiss explorer Johann Ludwig Burckhardt must have felt when he rediscovered the city one August day in 1812 after it had disappeared for more than 700 years - a forgotten city known only to Bedouins.