Time For A Breather

Running in an arrow straight line through the town of Clay Cross stand these now silent markers to a massive and otherwise invisible feat of civil engineering.
They are ventilation shafts to the Clay Cross railway tunnel, running some 150 feet below the town. For many years they would have rumbled and belched thick smoke as steam trains thundered through the darkness.
The tunnel is 1,784 yards long and was completed by George Stephenson in 1839, at a colossal cost of £140,000 (£10,430,000 today) and fifteen lives.