The 123-story Lotte World Tower, the capital's tallest building, is awaiting its grand opening on April 3. But on Wednesday, some of the more exclusive parts were unveiled for the first time, including the royal suite in the hotel, which costs a cool W20 million per night, and the ultra-fast elevator (US$1=W1,141).

The Seoul Metropolitan Government finally gave the final green light to the building's opening last week. With just 40 days to go, staff were still busy putting the finishing touches to the skyscraper.

An observatory on 118th floor has a sky deck with a vertiginous transparent glass platform 477.63 m above the ground. It is made with toughened 45 mm-thick glass "and it will not break even if an elephant stands on it," according to a press release.

Visitors look down from the glass observation deck at Lotte World Tower in Seoul.

The royal suite in the "six-star" Signiel Seoul hotel on the 100th floor will be the most expensive hotel room in Korea at 25 to 30 percent more than equivalent rooms in other hotels. It has a lavishly decorated reception, a meeting room and separate rooms for accompanying staff.

The hotel swimming pool on the 85th floor has two 20-m lanes.

The ultra-fast elevator takes just one minute and five seconds from the first basement level to the 118th floor. Ears popped, but otherwise it was a smooth ride.

Then there is the "Premier 7" luxury office space. One company can use the whole of each floor.

Ailing Lotte Group founder Shin Kyuk-ho is reportedly going to be moved to the 114th floor, while Lotte chairman Shin Dong-bin is planning to move into the 70th and the 71st floors, the highest floors of the Signiel Residence serviced apartments that mainly target rich people from the Persian Gulf.

Lotte corporate headquarters will move into floors from 14th to 38th. Lotte Corporation will move to the 19th floor, and Lotte Chemical will also move in sometime in the first half of this year.

On the 22nd floor, there is evacuation safety zone big enough to accommodate 1,680 people in an emergency. There are 1,680 gas masks and 1,680 LED flash lights, and two automated defibrillators and CPR machines, and two sets of heat proof clothes.

There are similar safety zones on 40th, 60th, 83rd, and 102nd floors, making it possible to reach any of them within 15 minutes from any part of the building and enough for 6,200 people.

For the sake of structural safety there are 509 sensors with cutting-edge technologies that monitor changes or unusual signs within the building through information delivered by GPS in real time. The control center has a dozen staff present around the clock to check fire safety, security, and the smooth running of machines.

The tower is also designed to withstand earthquakes and typhoons of the magnitude of the 1995 Kobe earthquake or hurricane Katrina.