The long line in the sand is whete I have been. My dragging left leg always leaves a trail to show where I have walked. At least I can always find my way back 
a bit like Hansel & Grettel with their crumbs only mine is always a mark on the floor or, as in this case, a line in the sand. The beach in question is Caleta De Fuste, Fuerteventura.
Thank you I will have a look at that hotel.