There are countless beautiful towns in the world that I've never even heard of.
There must be so many pretty towns in the world that I don't know about yet.
「世界にはまだ自分の知らない素敵な街が沢山あるんだろうな」＝ There are countless beautiful towns in the world that I've never even heard of. / There must be so many pretty towns in the world that I don't know about yet.
ボキャブラリー
there are ＝ ～がある
countless ＝ 数えられない
beautiful/pretty towns ＝ 素敵な街
world ＝ 世界
never even heard of ＝ 聞いた事もない
there must be ＝ ～があるんだろう
don't know about yet ＝ まだ知らない
イギリス 
