「渡る」(wataru) means to cross over something, like a bridge, road, or river. It is an intransitive verb. You often use the particle "を" to indicate the place you are crossing over. For example: 橋を渡る。(Hashi o wataru.) = To cross the bridge.

道(みち)や橋(はし)などを越(こ)えて、反対側(はんたいがわ)へ行(い)くことです。「〜を渡(わた)る」。例(れい)：道(みち)を渡(わた)る。