In Spain you can even spot an astronaut on an really old building in Salamanca, older than the US itself. But that's made as a hint/norm/law? among Historicians

In Spain you can even spot an astronaut on an really old building in Salamanca, older than the US itself. But that's made as a hint/norm/law? among Historicians/Restorers in order to say 'hey, this chunk is not the original, it had been restored recently because of maintenance'.