Tallinn's Old Town is one of the best preserved medieval cities in Europe and is listed as a UNESCO World Heritage Site. Tallinn is the major political, financial, cultural and educational center of Estonia. Often dubbed the Silicon Valley of Europe, it has the highest number of startups per person in Europe and is a birthplace of many international companies, including Skype. The city is to house the headquarters of the European Union's IT agency. Providing to the global cybersecurity it is the home to the NATO Cyber Defence Centre of Excellence. It is ranked as a global city and has been listed among the top 10 digital cities in the world. According to the Global Financial Centres Index Tallinn is the most competitive financial hub in Northern Europe and ranks 42nd internationally. The city was a European Capital of Culture for 2011, along with Turku in Finland.