Fossilised Coral

My blip had to be an indoor photo since it was such a miserable day.
Coral from Cuba.  The whole of Cuba is made of coral limestone.  It's the reason why the buildings in Havana have suffered so much, as the acid rain easily penetrates the porous rock and erodes it away.  If you look closely at the walls of some of the buildings (St Francisco de Asis church is a wonderful example) you can find fossilised corals including brain, fan and staghorn as well as tiny sea creatures. 
I tried to see if I could put a different background into the photo using a free trial of photoshop but it was beyond my skills.