わたるな

This sign is the whole of the Death by Kanji idea. A sign that looks like its saying 'cross here' is actually saying the opposite .

 

横断（おうだん）- Cross

禁止（きんし）- Prohibited

わたるな（渡るな）- Don't cross

横断禁止 on the sign is telling you 'Crossing Prohibited' and underneath わたるな is also telling you 'Don't cross'. Even though the sign is a picture of a man 'crossing' the road. Well, there is a red line underneath that has some sort of symbol of 'NO' that we are use to seeing in the west yet, it goes underneath the picture not making it very clear to the non-Kanji reader if it's OK or not OK to cross at this point.

Also, 

This sign uses a grammar structure only taught in intermediate or advanced textbooks of Japanese. Typically, when first learn Japanese な at the end of a word, phrase or sentence is an expression used by men to soften an assertion, desire, emotion or judgement.

But, 

At the end of a verb な becomes equivalent to ない and わたるな = 渡らない meaning 'don't cross'.

Other examples:

食べるな（たべるな）- Don't eat.
飲むな（のむな）- Don't drink.
走るな（はしるな）- Don't run.
歩くな（あるくな）- Don't walk.
書くな（かくな）- Don't write.
読むな（よむな）- Don't read.
払うな（はらうな）- Don't pay.
使うな（つかうな）- Don't use.
置くな（おくな）- Don't put.
するな - Don' do.

I hope this is helpful and if you have any questions please email me at deathbykanji@gmail.com.

以上です。

ジョシュア