Security has tightened at Oktoberfest after a deadly knife attack last month in western Germany, and officials are warning revelers

Every September, millions of tourists flock to Munich for Oktoberfest. However, the true centre of German beer culture lies three hours north in the medieval town of Bamberg.

Munich's Oktoberfest, the world's biggest beer festival, opened Saturday under heightened security following a string of attacks in Germany attributed to jihadists.