Complex sentence: Centre North East, formerly Corporation House as of its construction in 1974, is at 19 storeys and 70.7 m (231.9 ft), the tallest building in Middlesbrough.
Split into simpler sentences: Centre North East, formerly Corporation House, was built in 1974. It is, at 19 storeys and 70.7 m (231.9 ft), the tallest building in Middlesbrough.