Eucratidea ? (Ai Khanum), Afghanistan

Possibly, the old capital city of king Eucratides (if it wasn't the city of Bactria itself). His kingdom was Bactria, the part of Afghanistan to the north of Hindu Kush.
This coin is 58 mm across, the largest gold coin of antiquity, issued by Eucratides to celebrate his victory over his rival king Demetrios the 1st, also known as the King of India. It weighs 172 grams! This particular copy was discovered in Buskhara, Uzbekistan and was acquired by Napoleon the 3rd.