The tomb is of the mother of an admiral who is believed to have inspired the character of the ill-tempered Captain Haddock in Belgium author Herge's 'Adventures of Tintin'.
The first Tintin comic was published in the Belgian weekly "Le Petit Vingtième".
Apart from Tintin, the intrepid cartoon journalist, and his rocket, new Belgian passport will also include blue Smurfs.
Despite some high jinks, a new volume featuring the intrepid Gauls does little to counter the impression that the later works are running out of steam.
If it came to that, could Tintin have overpowered the snooper of people's private lives?
Steven Spielberg's computer animated 3D adaptation of Belgian comic book hero Tintin premiered in Brussels on Saturday, aiming to capture a new global audience for the adventures of the boy reporter with the trademark quiff.