Last year's event is a tough act to follow (SpaceShipOne, GlobalFlyer, HondaJet) but aviation is such a diverse endeavor, and AirVenture such a huge show, that there's never any shortage of things that you just can't see anywhere else. For instance, warbird buffs will be pleased to know that one of the largest gatherings of World War II heavy bombers will be at this year's show. One of two flying examples of the Lancaster bomber left in the world will be making the trip from the Canadian Warplane Heritage Museum to join a B-29, a B-24 and up to five B-17s at AirVenture. And, can you believe the most popular airplane of all time turns 50 this year? Cessna is planning a major celebration to mark 50 years of the 172 and its brawnier cousin, the 182. A specially designated area in the North 40 has been set aside for up to 500 aircraft to park together. By registering to park in the Cessna Base Camp, participants can camp with like-minded souls and be close to special events marking the big birthday.