"What do you think was the first food sold on the streets of New York?" asks Doug, our enthusiastic guide from Turnstile Tours. Our group stands in stony silence with furrowed brows. Everyone else is from an 18-35s Contiki tour and some of them haven't been to bed yet after last night's revelry. It's a little early for quizzes.
The unexpected answer is oysters. New York once had vast oyster beds and in the early 1900s they were sold by street vendors as a low-cost snack.
It's quite possible you can still buy oysters on the streets of New York today. It's estimated that 20,000 people work across the city's army of street vendors. And while buying a hot dog or a pretzel in Central Park will always be a quintessential New York experience, the city's street food scene is much more diverse than most visitors realise.
This walking tour from Turnstile Tours aims to showcase that diversity. Over the next two hours we'll visit a handful of the hundreds of carts and trucks that patrol Manhattan's Financial District. The plan is not only to sample their cuisine, which hails from all over the world, but also to learn about the challenges faced by the street vendor community.
Our first stop is Adel's #1, an Egyptian-run halal food cart that Doug claims "serves one of the best falafels in New York". He points to the long line of taxi cabs waiting nearby. "One of the easiest ways to tell whether a cart is any good is if it's frequented by people from the same region as the cuisine."
The falafels arrive and they're perfect – crisp on the outside; moist and flavoursome on the inside. Served on a bed of fragrant yellow rice, they're drizzled in mayo and a hangover-curing fiery red sauce that's a big hit with the Contiki-ites.
Despite operating from this intersection for more than 10 years, Adel's has no claim on this spot. Every cart has to return to a commissary to be cleaned each night, so theoretically someone else could take it tomorrow. Doug explains that, in practice, vendors have "an understanding".
From here we stroll to "Food Truck Alley", a section of Old Slip Street that's lined bumper-to-bumper with brightly-painted food trucks. Our destination is Domo Taco, an operation started in 2011 by Nelson Mui after he swapped his career in corporate IT for that of a chef. Launching a restaurant in New York is complicated, risky and expensive, so instead he bought a food truck and started making Asian-inspired tacos, burritos and quesadillas.
I sample Domo's trademark pork taco – a toasted corn tortilla filled with tender braised pork, red cabbage coleslaw and pico de gallo then smothered with cheese and sour cream. It's an inspired combination that's been so well received Mui has since opened a restaurant in Brooklyn's Crown Heights.
The obvious appeal of a truck is that you can move it around but competition for the best spots is fierce. Even though most trade happens during the lunchtime rush of 12-2pm, trucks need to be in position by 6am. Some owners even pay others to hold a space until they arrive.
Frustratingly, a 1950s bylaw means it's illegal to sell merchandise in New York from a metered parking space, which means the majority of trucks have to operate illegally and are regularly fined by police.
Helping vendors navigate the city's tricky regulatory system is the Street Vendor Project, a non-profit legal organisation founded by street food vendor turned lawyer Sean Basinski. The organisation provides legal and business development advice as well as running the Vendys, an annual awards ceremony that recognises the city's best street food. Turnstile Tours supports the organisation by donating 5 per cent of all its ticket revenue from the tour.
Our gourmet globetrot continues with a heart-starting Italian-style espresso from gourmet coffee cart Esprezzatura and a deliciously buttery beef-filled kati roll from Bangladeshi-run Biryani House. By the time we reach our final stop, Belgian waffle stand Wafels & Dinges, I'm not sure I can face another bite.
But then Doug appears with freshly baked golden brown waffles drizzled in chocolate, whipped cream and spekuloos, a spread made from "children's laughter and unicorns' tears". I take a deep breath and pull up a seat. This could take a while.
Air New Zealand flies via Auckland to Houston, Los Angeles and San Francisco with onward connections to New York. See airnewzealand.com.au.
Turnstile Tours operates its two-hour Food Cart Tour in Manhattan's Midtown and the Financial District. Adults $US48, children $US24. Vendors vary based on availability and tours include five or six generous tastings. See turnstiletours.com and streetvendor.org.
Rob McFarland was a guest of Air New Zealand, Brand USA and Turnstile Tours.