The vast majority of visitors in Greece in 2007 came from the European continent, numbering 12.7 million, while the most visitors from a single nationality were those from the <answer>United Kingdom</answer>, (2.6 million), followed closely by those from Germany (2.3 million). In 2010, the most visited region of Greece was that of Central Macedonia, with 18% of the country's total tourist flow (amounting to 3.6 million tourists), followed by Attica with 2.6 million and the Peloponnese with 1.8 million. Northern Greece is the country's most-visited geographical region, with 6.5 million tourists, while Central Greece is second with 6.3 million.
What is the single nation with the most visitors?
United Kingdom