Greatest evidence of the resurrection?

Strangely enough, this piece of evidence might be evermore indicative than that of the empty tomb. Imagine the following:

While visiting a foreign country you are suddenly seized by some terrorists and held hostage in solitary confinement for 90 days. During this time you are permitted absolutely no contact with the outside world. After three months (for no apparent reason) you are released and allowed to return home. Upon arrival however, you learn some incredible news. During your absence all Christian churches everywhere no longer gather for worship on Sunday, but instead assemble on Monday of each week. Your immediate question of course would be what in the world could have happened during those 90 days causing Christians to abandon their 2,000-year-old custom of worshipping on Sunday.

Yet this is exactly what happened in Palestine shortly after the resurrection of Christ. As ingrained as the Sabbath was in the hearts and history of the apostles, it would have taken some fantastic event to change their thinking here.