Dublin is the capital and largest city of Ireland, situated on the east coast at the mouth of the River Liffey. It was originally founded as a Viking settlement in the 9th century and grew to become the principal city under English rule. Major landmarks include Dublin Castle, Christ Church Cathedral, St. Patrick's Cathedral, and Trinity College, home to the ancient Book of Kells. Dublin prospered further during the Georgian era, resulting in iconic architecture like the Custom House and Temple Bar. Popular areas now include Grafton Street, Phoenix Park, and St. Stephen's Green. Dublin is known for Guinness, Irish whiskey, and legends like the lucky leprechaun.