Jeff Bezos & Lauren Sanchez Tied Knot at Historic Venice Island Amphitheater

There has been rampant speculation about where exactly Jeff Bezos and Lauren Sanchez would say their "I do's" for the epic days-long celebration in Italy ... and now we know it was all well-"staged."

Aerial snaps of Venice's historic island of San Giorgio Maggiore showed a portion of the ceremony took place at Teatro Verde -- "Green Theater" -- close to the edge of the tiny island.

See for yourself ... it's clear a massive structure was constructed for the event -- and it was more than big enough to hold the 200 superstars invited to celebrate with the couple.

Designed in 1952, the Teatro Verde's lower and upper circles seat 1,484 spectators ... so, again, space was not an issue!

A-listers have been flowing into the city all week ... from the Kardashian clan and Tom Brady to newly-single Orlando Bloom -- and ready-to-mingle Brooks Nader.

We know the ceremony is over and the (latest) party is underway ... and we also know Lauren looked absolutely stunning.

Vogue shared pics of her wedding dress ... revealing it's a Dolce & Gabbana gown -- which we knew it would be after seeing pics of them outside a storefront of the big-time brand in Milan -- with a high-necked, hand-appliquéd Italian lace.

Lauren also told the outlet this is the first time she's ever worn a formal dress that covered her chest. She calls it a "departure from what people expect, from what I expect -- but it’s very much me.”