In Germany there is no law that houses need smoke detectors installed, but when we moved in to our house, I purchased six of them and placed them at strategic points in the house according to the manufacturer's suggestions. That was five years ago and, apart from having to replace the nine-volt batteries once a year, they haven't been of much use. Until last night. I was upstairs reading The Three Little Pigs to my daughter, and the missus was applying war paint. Unknown to me, the Advent wreath with four huge lit candles was unwatched. Three of the smoke detectors started issuing a very loud signal. We ran downstairs to see the wreath in flames. I doused it with a bucket of water, and we then took the mess outside, opening all doors and windows to let out the smoke, the alarms ringing all the time. I had to disconnect the batteries from the detectors to silence them. Apart from ugly burn marks on our wooden floor (and a very frightened little girl), no damage was caused. If you don't have them: install smoke detectors! They can save your life.