Dublin is the capital of the Ireland. Its metropolitan population is 1.8 million. Dublin is home for about 25% of Ireland’s population. As of 2010, Dublin was listed by the Globalization and World Cities Research Network (GaWC) as a global city, with a ranking of "Alpha-", which places it amongst the top thirty cities in the world. Dublin is located at the face of the Liffey River and measures 115 square kilometers (44 sq. mi) of east- central Ireland. The city of Dublin is the most handsome Georgian city of the British Empire and is the living museum of its history & architectural splendors. The top experiences in Dublin are, the oldest Dublin Castle, the beautiful St. Patrick’s Cathedral, Ha'penny Bridge, an iron footbridge over the River Liffey, is one of the most photographed sights in Dublin and is considered to be one of Dublin's most iconic landmarks. The relaxing sites are Phoenix Park, Dublin zoo, St. Stephen’s Green, Dublin’s National Botanic Gardens. Adventurous sites include The Cliffs of Moher, Wicklow Mountains. Dublin is also famous for its museums, Little Museum of Dublin, the National Museum of Ireland. Newest monument is the Spire of Dublin, or officially titled "Monument of Light". It is a 121.2-metre (398 ft.) conical spire made of stainless steel and is located on O'Connell Street.