、。
I found something unusual in town.
Literal
Town-inside [at-で], rare thing [object-を] found.
町中で (まちなかで, 'in town, in the middle of town') sets the location. 珍しい物 ('unusual thing') is the object. 見つけました is the polite past of 見つける ('to find'). A simple, inviting opener that makes the reader want to know what was found.