The original sketch for the Biltmore, George Washington Vanderbilt's grand estate in the mountains near Asheville, North Carolina, laid out plans for a modest Tuscan villa. But ambition quickly took wing. The house swelled to 225 rooms and became - until 2012 when it was topped by the home of a billionaire in Mumbai, India – the world's largest residence ever built for a private citizen. Here's the story of the house that Vanderbilt built - from the gardens by Frederick Law Olmsted to the John Singer Sargent portraits that adorn its walls.