On 11 Jan 2006 02:20:26 -0800, wrote:

The towers of the Forth Road Bridge are different distances apart from
base to tip, can't remember what it is but it can be calculated.

I used to have the world's most complex tide gauge sharing my office
windowsill (back when I was laser student in Hull, with a desk on the
rooftop). An interferometer measured the distance to a retroreflector
mounted on the top of the Humber Bridge Northern tower. As the tide
moved, you could measure the bridge shifting.