The distance between Edinburgh Castle and the Palace of Holyroodhouse is almost exactly one mile. Midway between them is St. Giles Cathedral. It's an enjoyable budget travel experience to lace up your walking shoes and enjoy this stretch, known appropriately enough as the Royal Mile.
If you venture off on a side street, you might notice that the roadway plunges steeply downward. The Royal Mile lies along the spine of a hill that the castle defended. In fact, Edinburgh was years ahead of Hong Kong and New York in the practice of building upward rather than outward. Battles raged on the city's outskirts for years, and many of the most important addresses were shielded from this constant conflict along the Royal Mile and in layers of construction below it.
In addition to the castle, St. Giles and Holyroodhouse, you'll encounter some additional sites along the Mile that are free of charge: Edinburgh Museum, Parliament Square and The People's Story, which is a museum dedicated to daily life of residents through the ages.
