What does 88 mean?

88 is a secret way of German Neonazi groups to do the "Heil Hitler" greeting, which is in Germany, highly forbidden to do, to mention, etc.
So these guys use the number 88, which stands for the 8th letter in the alphabet. I found this 88 on a gas pipeline coming from Germany and delivered to Wales in 2006. It is different from grafitti.

69 and than 5

69 and than 5 belongs to a huge collection of photographs showing all sorts of numbers in all sorts of places and are probably inspired by the artists "pleasure" in maths...

Photo: 69 and than 5, taken in 2001 on board MV Temernik, Swansea, Wales, UK