Screw-pile

Screw-pile lighthouse
Lighthouse
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by blind Irish engineer Alexander Mitchell.
My sister is on a visit home from CO so we spent the day on the other side of the river doing a little Christmas shopping. She found some very nice gifts in the local shops.