Tadich Grill (1849) is not only one of the oldest surviving restaurants in San Francisco, it is one of the oldest surviving restaurants in the country. It's named after a Croatian, who introduced grilled fish to Americans. Croatians, supposedly, invented grilled fish.
Countries tried so far:
Africa: Algeria, Egypt, Eritrea, Ethiopia, Liberia, Madagascar, Morocco, Nigeria, Somalia, South Africa, Tunisia, Zimbabwe
Asia: Afghanistan, Armenia, Bangladesh, Bhutan, Burma, Cambodia, China, Georgia, India, Indonesia, Iran, Iraq, Israel, Japan, Jordan, Kyrgyzstan, Laos, Lebanon, Malaysia, Maldives, Mongolia, Nepal, North Korea, Pakistan, Philippines, Singapore, South Korea, Sri Lanka, Syria, Taiwan, Thailand, Turkey, Uzbekistan, Vietnam, Yemen
Europe: Albania, Belgium, Bosnia, Bulgaria, Croatia, Czechia, Denmark,
North America: Belize, Canada, Cuba, El Salvador, Guatemala, Honduras, Jamaica, Mexico, Nicaragua, Trinidad & Tobago, USA
South America: Argentina, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru, Venezuela
Oceania: Australia, Fiji, Samoa, Tonga