There are only so many ways to cross international borders, so my goal is to find as many creative ways as possible and do it!  Here's what I've come up with so far, let me know if you can think of any others!  

Fly   [US-> Israel // Israel -> UK // UK -> US // US-> Hong Kong // Hong Kong -> Australia]

Drive  [Israel -> Palestine]

Train  [US -> Canada]

Walk  [US -> Mexico]

Bike

Hitchhike

On the back of an animal

Boat

Swim

Tunnel under

Swinging from a vine

Rock Climb