Tel Aviv has 23 sister cities; Haifa has 20 in Europe, the United States, the Philippines, South Africa and China. Eighty Israeli cities have twinned with more than 300 cities worldwide. Rishon Letzion has 10 siblings; Tiberias has 4.

Some European cities have twinned with two different cities in the greater land of Israel. The Hague, Holland, for example, has twinned with Nazareth and Bethlehem, and Lyon, France, has twinned with Be'er Sheva and Jericho. These triplets, of an Israeli, European and Palestinian city, are often formed to make the cities eligible for financing from European Union cities, which condition their cooperation on such triplings. The Italian city of Pisa has twinned with both Acre and Jericho, forming warm ties that could herald a new role for sister-city arrangements.

Even very friendly people have difficulty maintaining strong, close relationships with 20 others. Israeli municipalities, which have very small external relations departments, find it hard to sustain such ties, but the incentive is great. In at least some cases, close relationships develop.

"City twinning arrangements start as a courting process," explains Sister Cities International spokeswoman Ami Neiberger-Miller. "If it works out, the acquaintance deepens and leads to the establishment of a family."

In this case, people really can choose their family, she says. However, a failure to nurture the relationship may leave the arrangement without any real content. A strong friendship is terrific, and has many positive economic, educational and cultural aspects, say those involved in such relationships.

Jacques Kemp, who heads the European Commission department for sister cities in Brussels, says there are more than 30,000 such arrangements throughout Europe. In 2007, the EU budgeted 11.5 million euros for sister city events.

"This is a way to foster friendship between European Union citizens," says Kemp. "We are involved in education, sports, administration, transportation, activities for senior citizens, and more."

Sister Cities International twins American cities with sister cities in 130 countries. When the relationship works well, residents of the cities form personal ties. When it doesn't, the relations fizzle out after a short while. Sometimes this happens due to municipal changes, and in some cases the image of a city or country is harmed as a result.

Acre, for example, signed a twinning agreement with eight cities around the world, and after the 1988 changing of the guard at city hall, communication ceased with seven of them. Now Acre has relations with only Bregenz, Austria (this failing was mentioned in the 2001 State Comptroller's Report).

Just like relations in a real family, tough times put the sister city agreements to the test. Neiberger-Miller cites the relationship between Ashville, North Carolina and Vladivostok, Russia, as an example.

"Although the cities had signed a sister city agreement, in practice no relationship or significant ties had developed, and the mayors were about to cancel the agreement," recalls Neiberger-Miller. "Then terrorists took over a school in Beslan, near Vladivostok. Two hundred people were killed in that attack, and the Ashville residents responded immediately. They raised huge sums of money to help people hurt in the attack, and many Ashville residents even went to visit their sister city in her time of need. From that moment, the relationship changed completely. The warmth continues to this day, and is based mainly on personal friendships between residents."

Rishon Letzion Mayor Meir Nitzan remembers a similar instance.

"On the first day of the [1991] Gulf War, when missiles were falling on the city, the mayor of our sister city Munster, Germany, called me from the airport and told me he was coming to visit, because he could not sit quietly at home while missiles were falling on his sister city."

Throughout that war, the mayor of Munster lived in Nitzan's home and accompanied him to sites that had been hit by missiles. Following that solidarity visit, ties between the two cities strengthened considerably, and they are still flourishing 16 years later.

There are two main approaches to the twin cities concept. Under the American version, relationships of this sort are formed through local friendship associations, usually volunteer organizations that are interested in building ties with other communities. These ties have no connection with the local authorities, and sometimes stem from a shared ethnic past or country of origin.

European cities have a different approach, which developed mainly after World War II. There, the closeness between sister cities is an integral part of municipal activity. At first, such relationships were formed mainly between communities in France and Germany, in order to foster friendship after the war and overcome decades of hostility. Today, notes Kemp, this is an important EU activity.

Israel's sister city relationships are based mostly on the European model, meaning the local authority is relatively involved. The Center for Local Government is usually a party to sister city agreements, but sources there were reluctant to discuss this subject.

"This issue is very important to me and close to my heart," said one of the center's officials, "but it is always presented in a negative light, and causes more harm than good. Twinning with another city is always described as some whim by a mayor looking for free trips abroad. This gives such an important concept a bad image. Thousands of youth who participate in exchange programs each year can tell you the importance of sister cities much more than anyone from the Center for Local Government."

Wanted: Jewish communities

Israel has two unique aspects. One is that it searches for sister cities with active Jewish communities, which can often guarantee the success of an agreement.

The second is the great importance placed on relationships with German cities. Haifa has five sister cities in Germany, Tel Aviv has two, and Netanya has five. All told, more than 100 Israeli cities and local authorities have relationships with Germany.

In the past, such relationships were strongly criticized. Menachem Ariav, the mayor of Nazareth Ilit, was decried for forming ties with Leverkusen, Germany and Klagenfurt, Austria, where the local Nazi party used to be very active. Ariav rejects this criticism.

"We must not forget the events of the Holocaust," says Ariav, "but we have to live with it and not stay isolated."

Nitzan says the relations between Rishon Letzion and Munster are good, and that the German city provides the opportunity for Rishon to learn progressive, quality administration.

Having something in common is often considered a condition for a successful relationship. Binyamina has one sister city - Tokaj, Hungary. Council chair Arye Zituni notes that the basis for the relationship is the cities' wine industry.

"We feel our relationship is important, as we can learn much from them in terms of tourism," says Zituni. "Every year Tokaj hosts one of the most famous wine festivals in Europe, and we can use that as a role model. We want to have our own date and fig festival."

Tiberias has sister-city relations with Montpelier, France. On its Web site, Montpelier has a page in Hebrew that states the ties were formed thanks to the French city's Jewish past.

"Montpelier has not forgotten that it was once home to an important Jewish community," states the Web page. "[Renowned medieval rabbi] Rambam (who is buried in Tiberias) taught here for a few years. Today the cooperation between the two cities, apart from cultural exchanges, has assumed a scientific and technological character, mainly in the water desalination field."