Istanbul has 62 twin towns from 4 continent in the world...

They are ;

From Europe

Tekirdag - TURKEY
Athens - GREECE
Baku - AZERBAIJAN
Barcelona - SPAIN
Belgrade - SERBIA
Berlin - GERMANY
Budapest - HUNGARY
Bucharest - ROMANIA
Durrёs - ALBANIA
Plovdiv - BULGARIA
Florance - ITALY
Kazan - RUSSIA
Kortrijk - BELGIUM
Cologne - GERMANY
Constanta - ROMANIA
London - ENGLAND
Odessa - UKRAINE
Prague - CZECH REPUBLIC
Rotterdam - HOLLAND
Sarajevo - BOSNIA
Stockholm - SWEDEN
Strasbourg - FRANCE
Skopje - MACEDONIA
Venice - ITALY
Warsaw - POLAND
Vienna - AUSTRIA
Oslo - NORWAY

From Asia

Ankara - TURKEY
Almaty - KAZAKH
Amman - JORDAN
Bangkok - THAILAND
Beirut - LEBANON
Busan - SOUTH KOREA
Jakarta - INDONESIA
Jeddah - SAUDI ARABIA
Dubai - UNITED ARAB EMIRATES
Grozny - RUSSIA
Ho Chi Minh - VIETNAM
Isfahan - IRAN
Johor Bahru - MALAYSIA
Kabul - AFGHANISTAN
Lahore - PAKISTAN
Merv - TURKMENISTAN
Osh - KYRGYZSTAN
Samarkand - UZBEKISTAN
St. Petersburg - RUSSIA
Surabaya - INDONESIA
Damascus - SYRIA
Shanghai - PEOPLE's REPUBLIC of CHINA
Shimonoseki, JAPAN
Tabriz - IRAN  
Xi'an - PEOPLE's REPUBLIC of CHINA

America

Buenos Aires - ARGENTINA
Caracas - VENEZUELA
Havana - CUBA
Houston - USA
Mexico City - MEXICO
Rio de Janeiro - BRAZIL 
Toronto - CANADA

Africa

Khartoum - SUDAN 
Cairo - EGYPT 
Casablanca - MOROCCO 
Constantine - ALGERIA 
Rabat - MOROCCO

Number of these countries doubled after 1993 ..