### Instruction:
Where is the annual indoor rowing World Championship?

### Input:
Ergometer rowing machines (colloquially ergs or ergo) simulate the rowing action and provide a means of training on land when waterborne training is restricted, and of measuring rowing fitness. Ergometers do not simulate the lateral balance challenges, the exact resistance of water, or the exact motions of true rowing including the sweep of the oar handles. For that reason ergometer scores are generally not used as the sole selection criterion for crews (colloquially "ergs don't float"), and technique training is limited to the basic body position and movements. However, this action can still allow a workout comparable to those experienced on the water. Indoor rowing has become popular as a sport in its own right with numerous indoor competitions (and the annual World Championship CRASH-B Sprints in Boston) during the winter off-season.

### Response:
The indoor rowing world championship is held annually in Boston during the winter off-season.