Kim Kardashian and Kanye West in Tropical Island Fortress to Avoid Paparazzi

Kim Kardashian and Kanye West wanted an appropriate setting to try and save their marriage, and we've learned, when they jumped on that private jet with their kids, they flew to a tropical island outside the country to take a trip that's very different from every other.

The Kardashians are famously photographed everywhere they go, but on this trip, it's designed specifically so there will be NO PHOTOS.

Sources with direct knowledge tell TMZ, the fam is staying in what is described as a "fortress" ... an estate that is so remote it's virtually impossible for trespassers to get close.

It's interesting ... there is total radio silence as to how the vacation is going. As we reported, this could be the final test on the marriage. They have had relatively little contact over the last few months, and Kanye's pronouncements at the South Carolina campaign rally and on twitter clearly didn't help.

We broke the story ... last week Kim flew to Wyoming to see Kanye, and the reunion was tearful and tense.