Translation:My city is very big.
Town and city are very strictly defined in Japan. The name of every town, city, and village in Japan has a suffix attached denoting which type it is.
～市 (shi) city
～町 (machi) town
～村 (mura) village
But 街 (machi) can refer to any place that you live, I believe the nuance would be a place with many streets.