Time travel. It seems very far into the future, or not possible at all, but if it were possible, would that be considered a wonder? Most likely.
Man kind is currently limited by time in that we are unable to see into the past or the future. Such an accomplishment, even if it were only a few seconds, would propel us into a world of new possibilities. The difference from being unable to travel and able to travel one second would change the outcome of mankind and the technology afterwards. In fact, it would add a dimension into our world! Who knows...maybe someday people would be able to see the first wonder being created!