Bridges

All my life there have been two bridges at Queensferry. Soon, there will be three. If I have children they will never know it to be different.
Me and dad stopped at the vista point just past the 'ferry today to have look at the progress. I am at a loss as to how you technically go about building a bridge - how do you even go about lowering these bases into the water?
A lovely afternoon with my granny and grandad and some most spectacular news... my wee brother has a new job!