The "most expensive street in the world" moniker changes depending on currency fluctuations and local economic conditions from year to year. For several years starting in the mid-1990s, the shopping district between 49th and 57th Streets was ranked as having the world's most expensive retail spaces on a cost per square foot basis. In 2008, "Forbes" magazine ranked Fifth Avenue as being the most expensive street in the world. Some of the most coveted real estate on Fifth Avenue are the penthouses perched atop the buildings.