Apple today issued invitations for its upcoming iPhone 6 event on September 9, which is also said to include its much-anticipated wearable device. According to the invitations, Apple is planning to host the event at the Flint Center for the Performing Arts at De Anza College in Cupertino, the same location where Steve Jobs introduced the original Mac 30 years ago.

For the occasion, it appears that Apple has been building a massive structure on the campus, which has been kept under tight wraps with a white barricade. A MacRumors reader has sent in images of a mysterious structure at the Flint Center, which appears to span three stories and is protected by "scads" of security people. Administrators had previously declined to comment on what the structure is for, stating only "We are not at liberty to discuss that due to client wishes."

Image of mysterious structure taken on August 20

Apple has not held an event at the Flint Center in many years, so the company's return to the site of the original Mac unveiling suggests its upcoming announcement will be a major one. The Flint Center has a much higher seating capacity than other venues where Apple has unveiled products in the past, including the Yerba Buena Center and its own Cupertino campus.

Earlier this year, Apple iTunes chief Eddy Cue said that Apple's got the "best product pipeline" he'd seen in his 25 years at the company in the works, and Tim Cook promised "really great stuff" in new product categories.

Despite the cryptic "Wish we could say more" message on the media invitations, rumors have suggested Apple is planning to unveil both the iPhone 6 and a new wearable device at the September 9 event.

It is unknown whether Apple has plans to broadcast the event on the web and Apple TV as it has done for recent events, but MacRumors will provide live coverage both on MacRumors.com and through the MacRumorsLive Twitter account.