Some passengers on long-haul flights have been left puzzled by an unsettling discovery marked on their inflight maps.
The flight maps appear to show the locations of shipwrecks and their year of sinking.
"Titanic; 1912" and "Thresher; 1963" were among some of the more obvious wrecks showing up on the flight information systems of Swiss Airlines, Emirates and American Airlines.
Taking to Twitter the travellers were not alone in thinking it was an odd inclusion on the flight maps, and one that did not fill them with confidence.
"Dear @AmericanAir, are you including shipwreck locations on your in-flight maps on transatlantic flights to make your customers feel more at ease about the safety of international travel?" asked Thomas Weber who tweeted the airline for further information.
Among some of the more unsettling and tragic inclusions is the RMS Lusitania; 1915, a civilian liner which was sunk during the First World War and can be clearly seen on flights out of Dublin.
"Is it to reaffirm me that flying is safer than crossing the Atlantic by ship?" asked Florian Nicklaus after spotting the wreck of the Titanic on his inflight map.
However the company behind the software which is used by most airlines said that for many passengers these historical shipwrecks were a "point of interest".
Collins Aerospace which supplies the software and datasets to airlines says that it's up to the airlines what they choose to show passengers or not.
When ordering the map software it is up to the airlines what they want to include and many choose to show these "points of interest".
"The choice to provide the points is completely based on the airline's selection and not forced by Collins Aerospace. It is a configuration designed into our software, similar to background colour or logo on an airplane," the company told the MailOnline.
Theses shipwrecks were once important data points for nautical crossings highlighting potential danger, though today the wrecks are merely a novelty feature for bored passengers to contemplate.