The distance from Sydney to Glenbrook – the east gateway to Blue Mountains National Park – is about 40 miles. Your main route will be The Great Western Highway. It is an easy drive now but almost impassable before the 19th century. In 1831, General Major Thomas Mitchell was commissioned to build a road up the eastern escarpment of the Blue Mountains. He hired stone mason David Lennox to become the Superintendent of Bridges. When a team of convicts finished his first project in 1833, the bridge was named after him. Lennox Bridge is the oldest stone arch bridge on Australia’s mainland.