World's smallest working 'lighthouse' - powered by vegetable oil

Meet the man who runs the world's smallest working 'lighthouse' - which can shine for three miles and is powered by vegetable oil. Garry Irvine looks after the historic 23ft Harbour Light Tower - climbing its 24 steps three times a week. The famous tower replaced an original lighthouse which was constructed across the street in 1811. It provided much-needed light to the well-travelled River Forth in Scotland – but due to its positioning the original light struggled to illuminate the entire crossing. Students then began to work with civil engineer Robert Stevenson with the aim of finding a suitable solution.