Monaco, the small country well-known for its glamorous casinos and rich residents, is now garnering reputation for being a home to what could become the most expensive apartment in the world.

The apartment in question is the 3,300 sq. m. quintuplex luxurious living place called "Sky Penthouse" in the Odeon Tower, which is in the final stage of completion. The tower soars to the height of 557 feet, which will make it the second-tallest building along the Mediterranean coastline.

Developed by luxury real estate giant Groupe Marzocco, the twin skyscraper will contain 70 apartments. The building will offer apartments with 1-6 bedrooms, two sky duplexes and the multi-story penthouse.

The multi-story penthouse, Sky Penthouse, will offer a waterslide that will allow the owner to enjoy a slid straight from the dance floor to the swimming-pool. It will also offer an unobstructed clear view of beautiful Mediterranean Sea.

In addition to swimming-pool and an entertainment, it will offer five bed rooms, living-room, dining-room and a wellness centre, including a gym, sauna and private spas.

Scheduled to be completed by September 2015, extremely luxurious apartment is expected to fetch nearly 300 million Euros (US$400 million) when it will go on sale next year.