X Marks the Spot

Mario & I went down to the wetlands today to photograph birds in flight. Every single one of my photos was complete and utter rubbish, so when I got home I binned the lot.

This photo is of one of the concrete foundations supporting the rail bridge. I photographed it because I liked how the sunlight was filtered through some gaps up above somewhere. I don't know the significance of the XXXV (isn't that 35 in roman numerals?), and I don't know what the symbol underneath means, although I suspect it may be Latin.

It's very mysterious.