Short answers, pulled from the story.
The Ostankino Tower stands 540.1 meters tall. It is the tallest free-standing structure in Europe and ranked 15th tallest in the world. Between 1967 and 1974 it held the title of tallest free-standing structure on Earth, surpassing the Empire State Building before being overtaken by the CN Tower in Toronto at 553 meters.
Nikolai Nikitin designed the Ostankino Tower. He proposed a reinforced concrete structure instead of the originally planned lattice metal tower, drawing partly on a Stuttgart tower completed in 1956 and on concepts developed by scientist Yuri Kondratyuk in the 1930s. Nikitin incorporated 150 internal steel cables and relied on a shifted center of gravity for stability.
On the 27th of August 2000, a fire broke out at 460 meters inside the Ostankino Tower, destroying the Seventh Sky restaurant and severely damaging the structure. Of 150 internal steel cables, only 19 remained intact. Three people died, all of Moscow lost television reception for months, and the tower stayed closed to visitors until 2008.
The Ostankino Tower opened in 1967 to coincide with the 50th anniversary of the October Revolution. Construction began in 1959. It replaced a 1922 Shukhov lattice tower on Shabolovka Street that had reached the end of its operational life.
The Seventh Sky is a revolving restaurant inside the Ostankino Tower, situated between 328 and 334 meters above the ground. Its three halls, named Bronze, Silver, and Golden, each held up to 80 guests and completed one full rotation every forty minutes. It operated for 33 years before the 2000 fire destroyed all three floors, and partially reopened in 2016-2017 after a 16-year reconstruction.
The Ostankino Tower was the first free-standing structure in the world to exceed 500 meters in height. It held the record as the tallest free-standing structure in the world from 1967 to 1974. It remains the tallest free-standing structure in Europe. The tower also served for many years as the world's tallest flagpole.