Wikipedia
.istanbul
.istanbul and .ist are approved top level domains (TLD) for the Internet. It is a community-based sponsored top-level domain by Istanbul Metropolitan Municipality and subsidiary Medya A.Ş. According to the Medya A.Ş., .istanbul will improve awareness on İstanbul's historical heritage and help economic growth by allowing unlimited and open registration of the names.
Along with TLDs such as .cat and .asia, .istanbul and other new TLDs fall into the new category of GeoTLDs.