Journalists given a tour Tuesday saw sweeping if hazy views of the Tokyo skyline.
It took about 50 seconds in a high-speed elevator Tuesday to zip up to the lower observation deck at 1,148 feet, and another 30 seconds to reach the higher deck at 1,476 feet.
The Skytree has a restaurant and two cafes on the observation decks, a vertigo-inducing glass floor that allows visitors to look straight down, and an emergency staircase with 2,523 steps.
The tower was constructed with extremely strong steel tubes surrounding a central concrete column that are structurally separate from each other in the tower's mid-section. In the event of an earthquake, the concrete core and steel frame are designed to offset each other to reduce the building's overall motion.
The Skytree has been built to stand firm even if a magnitude 7 quake were to strike beneath the building, said Sho Toyoshima, a spokesman for Tobu Tower. He said the tower sustained no structural damage from the magnitude 9.0 quake that struck off Japan's northeastern coast last March, even as it was being built.
The Skytree is expected to bolster television and radio transmissions in the capital region. Owners hope it will also become a new tourist destination in Tokyo.