From Radio Prague:

For twelve years, Czech archaeologists have been helping their Bulgarian colleagues in the excavations of an Ancient Greek market town in central Bulgaria. The twelve years of work has yielded valuable results, including a hoard of coins, and discovered a surprising connection between the ancient town and the Czech Lands.
Pistiros Pistiros
The river port of Pistiros was founded in the 5th century BC by a local Thracian ruler. From the excavations we know that wine from Greece was imported to the town in large amphoras. Other pottery was found in and around the remnants of houses and also a hoard of treasure was unearthed from one of the ruins. Professor Jan Bouzek was head of the team.
"Well, it was a hoard of some 561 coins. They were buried just before the Celtic invasion which came there in 278 BC. They were put into a locally made jar, just in a hurry, because the Celts were apparently already attacking the city."
Hoard of coins Hoard of coins
Over a thousand coins were unearthed on the site, minted in various Greek cities and bearing the portraits of many rulers, including Philip II, who caused considerable damage to Pistiros around the year 345 BC. The city was destroyed by Celtic invaders some fifty years later and never fully recovered. Interestingly, some of the attackers apparently came from what is now the Czech Republic.
"In the destruction we found several Celtic weapons which were partly burnt and most of them are not well preserved with the exception of one arrowhead. But we found in the ruins that at the time of the looting of the city they lost one of the typical fibulae (buckles) of the so-called Duchcov type which were especially well-known from a great hoard in Duchcov and which must have been made in this country. Some of the Celts from these parts apparently participated because they were also one of the four tribes which founded the kingdom of Galatia. They were Celts living in the northern part of this country."
Duchcov fibulae Duchcov fibulae
The fruits of the 12-year Czech-Bulgarian joint research were first presented to the archaeological community last week in Prague at the Third International Congress on Black Sea Antiquities. As Professor Jan Bouzek says the beginnings of Czech-Bulgarian cooperation in archaeology date back to the 19th century.
"Well, the history is much longer. Both my professors who did archaeology epigraphy were working in Bulgaria. And 80 percent of the founders of Bulgarian archaeology were the Czechs. They were the Skorpil family, Professor Vaclav Dobrusky - who was actually the first person who had any knowledge of our site. Vaclav Dobrusky was the founder of the Bulgarian National Archaeological Museum and he discovered the first inscription on the [Pistiros] site. It was long forgotten and only discovered much later by my friend Mieczyslaw Domaradski who was Polish-born but lived and worked in Bulgaria. He really discovered the city much later."

... photos and an audio report accompany the original article.