philly has "the duck" what does your city have?
 

philadelphia now has a tour bus that not only takes you by the liberty bell but then drives down a boat ramp and chugs down the delaware river for great city views.
this amphibious craft is called "the duck"
does chicago have a bus that tours the loop and then plunges into lake michigan?
does new york's double decker buses float by the statue of liberty?
does a tour of movie stars homes in hollywood include whale watching?

We have/had "the duck" in the Tampa Bay area too, but I believe I heard it just "went under"...pun intended--not a viable enterprise after a good trial.

They wanted to do it in Savannah when we lived there, and City fathers collectively rolled over in their graves at the idea of that thing running though the squares. Bad enough we had buses, we didn't need aquatic vehicles as well.

Duck Tours have been popular in Boston for years!

Duck Tours in Austin too....

Ducks in Branson, Missouri and
Chattanooga, Tennessee

DC has the ducks, too.

Toronto has the Hippo, which is bigger than I remember the Boston duck I saw a few years ago.

Drives around downtown,and then into Lake Ontario for a while.

Ottawa had a converted big Ford pick up truck which sank in the Ottawa River, with some lives lost, a couple of years ago. The problem, in simplified terms, was a roof and windows that didn't open, and a poor conversion. Turns out that the rules in Canada for doing these kinds of conversions were badly written and confused.

The Toronto Hippo,however, is bigger, and meets a different set of rules that are apparently much better.

BAK

San Diego has Duck or Seal tours (sea and land) I think they are affiliated with Old Town Tours.

No Duck in Asheville, NC, but we've got an authentic London omnibus parked in a tiny lot at the corner of Biltmore and Aston that's been converted into a popular coffee shop.

Does that count in the world of weird vehicles? The only tourist vehicles we've got roaming our streets are motorized trolleys.

We have Duck Tours in Honolulu, too....

And home of the very first and original Duck Tours : Wisconsin Dells

NYC can "duck" this question as it already has the Circle Line Cruises:sail down the Hudson, cruise around the Statue of Liberty, travel up the East River, and under the Brooklyn, Manhattan and Williamsburg Bridges all the way to the United Nations and back.

London, England, has these land-and-water tours, I believe they call them frog tours.

We've got the duck in Seattle too... Although one sank a yr or two ago.. but they're back up and running!