Complex sentence: Another Dunston landmark was the Derwent Tower, (commonly known as the "Dunston Rocket"), a tower block that was once the highest in Gateshead, which was designed by the Owen Luder Partnership and completed in 1973.
Split into simpler sentences: Another Dunston landmark was the Derwent Tower, (commonly known as the "Dunston Rocket"), a tower block that was once the highest building in Gateshead. It was designed by the Owen Luder Partnership and completed in 1973.