此地無銀三百兩

Etymology
The first half of a longer sentence:, literally “There are no 300 taels of silver (buried) here. The neighbour Wang Er did not steal (the silver).”

It is said to come from a story about a man named Zhang San. According to the story, he buried 300 taels of silver in the ground with the banner “There are no 300 taels of silver (buried) here” so that no one would steal them. But his neighbor Wang Er saw through the lie and dug up the money, leaving the banner “Your neighbour Wang Er did not steal (the silver)”.

Idiom

 * 1) a clumsy denial resulting in self-exposure; a very poor lie which reveals the truth; protest one's innocence too much; the lady doth protest too much