Strange Insect

A few days ago I found this large insect sitting totally motionless for a long time on a pavement here on La Gomera (see photos below). Lots of people took photos but nobody seemed to know what it was. There was an easterly current of air at the time, so it probably came from Africa and had to rest after the long journey. If anyone knows what it is, please leave a comment to enlighten me. 
UPDATE: Thanks to reader Kim Houmoller (see 2 comments below) the mystery appears to be solved: It is a rare moth, Acherontia atropos

..and having looked it up on Wikipedia, I must agree with Kim Houmoller, because it can be identified by the vaguely skull-shaped pattern on its back,see:http://en.wikipedia.org/wiki/Acherontia_atropos
It is even featured in a music video by Massive Attack.

Seen on a pavement on La Gomera