Massive? It was about the size of a football field. I don't think it mattered much because it happened in the middle of nowhere and would not even have been noticed but for some holiday makers camping in the vicinity; it certainly doesn't qualify as a portentous event signifying the beginning of the last-days. By the way, the sink whole swallowed one empty 'trailer' and one empty car - the owners were away doing something in some other holiday location. Nobody was killed and no camp-site was swallowed.
PS: Russia isn't attacking Syria it is supporting the government of Bashar Al-Assad by bombing its enemies. It is attacking Syria less than the USA currently is.
PPS: