The influence of Rome in the ancient world began to grow around the 2nd century BC as the Republic expanded across Southern Europe and North Africa. For the next five centuries, Rome would govern much of the known world (of traditional Greco-Roman geography). The cultural influence of the local language of Rome (Latin) as well as Roman art, architecture, law, religion and philosophy was immense. The city of Rome adopted as its nickname Caput Mundi, attributing this to its perception of an enduring power of Ancient Rome and the Roman Catholic Church.
Constantinople was built as the second Rome by Emperor Constantine in 330 AD.
The Byzantine Empire lasted for over a thousand years with the center always at Constantinople, except between 1204 and 1261, when it was centered in the capitals of Nicaea, Trebizond, and Arta. The city was seen as the "Capital of the World" because of its prime trading position in the center of the medieval world. This privileged position continued even as the capital of the Ottoman Empire. The city was also the center of half of the Christian world as the seat of the Patriarch of the Eastern Orthodox church. Napoleon Bonaparte is quoted as saying, "If the Earth were a single state, Constantinople would be its capital." Today, the city's name is Istanbul.
The capital of the British Empire was London - though the empire has since passed, London is one of the world's leading business, financial, and cultural centres, and its influence in politics, education, technology, entertainment, media, fashion and the arts all contribute to its status as a major global city. Many of the world's largest corporations have their headquarters in London, the city taking a central role as a part of the wider global economy. In addition London in time and on maps is on the Prime Meridian, running directly through Greenwich (also known as the Greenwich Meridian), with its time zone as GMT+0 (UTC+0). The decision made at the International Meridian Conference was due to the dominance of the British Empire; for logistical reasons, and because the United Kingdom and London remain a major global influence, this position of the Prime Meridian remains.
Numerous sources have claimed that London had eclipsed New York City as a financial centre, establishing itself as the financial capital of the world. In addition to this, London has been ranked as the world's capital city in terms of culture, business, Technological readiness and overall economic clout, as well as attracting the most foreign investment of any global city.
The situation of numerous iconic landmarks, such as Big Ben, St Paul's Cathedral, Tower Bridge, the Houses of Parliament, and Buckingham Palace, as well as modern architecture such as the Gherkin, The Shard, the London Eye and the O2 drew approximately 16.7 million international tourists in 2013, establishing London as the most visited city in the world for international tourists.
Adolf Hitler, the dictator of the Third Reich, as part of his proposed New Order, planned to make Berlin the "Caput Mundi", directing Albert Speer to formulate the Welthauptstadt Germania—a plan to rebuild Berlin in an Imperial architectural style. The central edifice of Berlin would have been the Volkshalle, from which Hitler would have issued his Imperial decrees as the absolute ruler of Europe.
New York City, the most populous city in the United States, is sometimes described by the Latin phrase "Novum Caput Mundi" ("New Capital of the World"); or more commonly by the English phrase, "Capital of the World". A leading global city, New York exerts a significant impact upon commerce, finance, media, art, fashion, research, technology, education, and entertainment, its fast pace defining the term New York minute. Home to the headquarters of the United Nations, New York is an important center for international diplomacy and has been described as the cultural and financial capital of the world, despite not being the modern capital of the United States or even of New York State. As many as 800 languages are spoken in New York City, making it the most linguistically diverse city in the world.
Numerous national and international private corporations have headquarters in New York City. Anchored by Wall Street, in Lower Manhattan, New York City has been called the world's principal financial center as well as most economically powerful city and is home to the New York Stock Exchange, the world's largest stock exchange per total market capitalization of its listed companies. The New York City metropolitan region is defined by both the Metropolitan Statistical Area (19.9 million residents in 2013) and the Combined Statistical Area (23.5 million residents in 2013). In 2013, the MSA produced a gross metropolitan product (GMP) of nearly US$1.39 trillion, while in 2012, the CSA generated a GMP of over US$1.55 trillion, both ranking first nationally by a wide margin and behind the GDP of only twelve nations and eleven nations, respectively.
New York City has been ranked first among cities across the globe in attracting capital, business, and tourists. Tourism is vital to New York City, and many districts and landmarks in New York have become well known, as the city received a record high 56 million tourists in 2014, generating an all-time high US$61.3 billion in overall economic impact for New York City in 2014. Several sources have ranked New York the most photographed city in the world. Times Square, at the hub of the Broadway theater district, is nicknamed The Crossroads of the World, The Center of the Universe, and the "heart of the world".
The capital of the United States of America and the seat of the U.S. federal government, Washington, D.C. also holds the headquarters of important international organizations such as the World Bank, the International Monetary Fund, and the Organization of American States. The signing of the North Atlantic Treaty took place in Washington; establishing NATO which took part in the Cold War, and by its end, Washington was dubbed by the Washington Post as the capital of the world.