The Amazing Race's co-creator and executive producer Elise Doganieri has teased Sunday night's finale of the show's 23rd season was purposely designed to "drain" the Final 3 teams and especially difficult and challenging.

Doganieri promises The Amazing Race's upcoming finale will be the most "mentally, physically and even emotionally" exhausting yet, as the challenges were created to "drain" the Racers of "every strip of confidence" they had left.

"It gets challenging every season to try and come up with new and exciting things, but to go along with the creative, you really do have to have a great cast, and we have had an incredible cast this season," Doganieri told E! News.

"So for this finale, which is a leg that I scouted and put together, we really wanted to find something challenging and difficult. We don't ever want to just give the million dollars away... After 12 legs of the Race, we really test the contestants... We really drained... any last little bit of emotion that they had out of them, and we really pushed them to come together as a team."

The final leg of the Race will begin in Tokyo.

"They're going to start off in Tokyo and they basically become human bowling balls, so the Japan stuff is super funny," Doganieri said of their first task.

Afterwards, the next demanding challenge will require the Racers to undress and get into a confined space filled with water.

"We also have a task where they're going to strip down to their underwear or their bathing suit in Tokyo and they basically have to get into a giant phone booth," she told E! News. "It really is like a giant fishbowl filled with water and they have to make a phone call in the bottom of the booth while holding their breath."

Following four continents, nine countries and more than 35,000 miles, the Final 3 teams will then cross the finish line in Alaska.

"Ultimately the final three teams are going to have to go to Alaska and they go full out. They have to cross a glacier and sprint to the finish line," Doganieri added.

The remaining four teams heading into Sunday night's two-part finale are as follows: "Cousins" Leo Temory and Jamal Zadran, "Exes" Timothy Sweeney and Marie "Reebs" Mazzocchi, "Dating Couple" Jason Case and Amy Diaz, and "Married ER Doctors" Nicole Jasper and Travis Jasper.