周幽王的身边有一位美丽的妃子，她的名字叫褒姒。
为了讨好她，幽王甚至把太子宜臼废为庶人，并将皇后打入冷宫。
虽然褒姒被立为皇后，但她总是闷闷不乐，脸上总是一副冷漠的表情，从来没有笑过。
幽王为了让她开心，想尽了各种办法。
有一次，幽王很困惑地问褒姒：“为什么你从来都不笑呢？”
褒姒回答说：“我天生就不喜欢笑。”
幽王无计可施，只好下令：“谁能使褒后笑出来，就赏赐他一千两黄金。”
这时，虢公向幽王出了一个主意：“以前先王为了防止西戎入侵，在骊山下建造了二十多座烽火台。一旦有敌人来犯，就会放狼烟示警，附近的诸侯们就会赶来救援。现在天下太平，烽火台很久都没有用过了。大王不如和褒后来到骊山，晚上点燃烽火，诸侯们必定会急忙赶来救援。当他们看到没有战事发生，只是您和褒后在饮酒作乐时，一定会感到非常失望。这样，褒后也许就会笑了！”
幽王听了这个建议，决定照做。
当天晚上，他命令人们点燃烽火。
附近的诸侯们看到了，果然纷纷赶来救援。
但他们只看到幽王和褒姒在楼台上饮酒作乐，并没有任何战事发生。
大家都愣住了，面面相觑。
等他们明白这是一场恶作剧后，都无奈地领兵回去了。
褒姒看到这个场景，忍不住哈哈大笑起来。
幽王看到褒姒终于笑了，于是就赏给虢公一千两黄金。
然而，这一笑也埋下了亡国的祸根。
后来，“千金一笑”就成了不惜重价，博取美人欢心的代名词。
King You of Zhou had a beautiful concubine by his side, her name was Bao Si.
In order to please her, King You even demoted the Crown Prince Yi Jiu to commoner status and exiled the Queen to the cold palace.
Although Bao Si was made queen, she was always melancholy and had an indifferent expression on her face, never having smiled before.
King You tried every means to make her happy.
Once, King You asked Bao Si in confusion, "Why don't you ever smile?"
Bao Si replied, "I was born not liking to laugh."
King You was at a loss and could only issue an order: "Whoever can make Queen Bao laugh will be rewarded with a thousand catties of gold."
At this time, Lord Guo offered a suggestion to King You: "In the past, our ancestors built more than twenty beacon towers at the foot of Mount Li to prevent invasions from the Western Rong. Once there were enemies attacking, they would send up smoke signals as a warning, and the nearby feudal lords would come to their aid. Now that the world is peaceful, the beacon towers have not been used for a long time. Your Majesty might as well take Queen Bao to Mount Li and light the beacons at night. The feudal lords are sure to rush to the rescue. When they see that there is no battle going on, just you and Queen Bao drinking and making merry, they will surely feel very disappointed. Maybe then Queen Bao will laugh!"
King You listened to this suggestion and decided to do it.
That night, he ordered people to light the beacons.
The nearby feudal lords saw it and rushed to the rescue one after another.
But they only saw King You and Bao Si drinking and making merry on the tower, and there was no battle going on at all.
Everyone was stunned and looked at each other.
When they realized that this was a prank, they all led their troops back reluctantly.
Bao Si saw this scene and couldn't help laughing out loud.
King You saw that Bao Si finally laughed, so he rewarded Lord Guo with a thousand catties of gold.
However, this smile also sowed the seeds of downfall for the country.
Later on, 'A Smile Worth a Thousand Pieces of Gold' became a metaphor for spending a high price to win the favor of a beauty.
