Four penthouses sit atop the gracefully curved Ritz-Carlton Residences at Sunny Isles Beach, Miami with unobstructed 360-degree wide water and surrounding beach-town views. The unit spanning the entire 51st floor sold last week for $21 million, according to CEO and President of Fortune International Group, Edgardo Defortuna, via the Miami Herald. The sale is the latest in a series of high-end Miami penthouses to sell in recent months.

The building rises 52 stories, while this particular unit on the second-to-top floor spans 7,760 interior square feet with an additional 3,000 square feet of exterior balcony space. Four bedrooms, six full bathrooms and one half bath grace the interior, in addition to service quarters, a gym, theater and a den. Outside, a garden and pool are incorporated into the terrace.

The buyer is an undisclosed domestic party, according to Defortuna. About 80 percent of the building's 209 units have been sold to-date. Residents may enjoy amenities that include a spa, two pools and kids' play areas, in addition to the highly-regarded concierge service Ritz-Carlton Residences are known for.

Photography via The Ritz-Carlton Residences Sunny Isles Beach, Miami