Greece historically was once a major collection of small independent city states or small countries such as Athens and Sparta. These little countries occasionally fought historic wars with Persia (as depicted in the film 300), and Troy (depicted in the film Troy).
Ancient Greeks played a pivotal role to the development of the Western World civilisation.
Athens is still the capital of Greece.
Modern Greece is a Representative democracy and a member of the European Union. Greece is a Republic. The Greek parliament elects a president. There is separation of powers between the legislature, the executive and the judiciary. The constitution should guarantee Civil liberties.
Unfortunately Greece got into serious trouble because the Greek government spent more than it took in Taxes year after year and expected the other countries of the European Union to bail them out. The other European nations aren't willing to foot an unlimited bill. Greece also has a serious problem of tax aversion, which helped to crumble the Greek economy into dust. Greece is one of Europe's most corrupt countries. As so often happens corrupt politicians got Greece into the mess and the ordinary People are having to make all the sacrifices to sort it out. Many Greeks have been forced into Poverty. Extremists, notably the Neo-Nazi, Golden Dawn are strong in Greece due to Economic trouble.
Greece and the USA compared
Greece isn't the only nation to spend more than it takes in taxes. The United States also has problems because Republicans refuse to allow the necessary taxation to pay for public spending, see Starve the Beast.