Did you notice that a few numbers in Zagreb tram line are missing? There's 9 and 11, but what happened to 10?
Zagreb actually used to have a 10 (and a 16, but more on that in one of the next Zagreb in History sections.) The line became operational in the ‘30s and it was discontinued in the ‘80s.
It used to connect Savski most and Borongaj via the Main Railway Station (Glavni kolodvor). A reorganisation of lines was introduced in the early ‘80s, when a zero was added in front of each line. This caused lines 1 and 10 to overlap, so line 10 was discontinued.
Line 10 at the Savski most Terminal, 1970s
It was briefly reintroduced in March 2013, due to works on the rail system, causing nostalgia among the older citizens and interest as to why it was doscontinued among the younger ones.