This is what remains of a Mexican tour bus that skidded off the road Friday leaving 21 dead.<br/> <br />At least 29 were injured in the crash, in the state of Nayarit.<br/> <br />Officials said children were among the dead, but it wasn't known how many lost their lives.<br/> <br />The bus -run by Express Oro Tours - was heading to a resort in Narayit.<br/> <br />Investigators say brake failure and driver fatigue could have played a role in the fatal crash.<br/> <br />Andrew Raven, Reuters
