Here are other tours that offer insight into lesser-known "attractions."
Nighttime factory cruise tour, Kanagawa, Japan
In recent years, many Japanese have fallen victim to "kojo moe," or "factory infatuation."
Nighttime tours of illuminated industrial areas are especially popular.
Highlights of the tour in Kanagawa include the Keihin Industrial Area -- one of the four major industrial areas in Japan -- and the chance to toast Japan's factories with a "Nostalgic Nights" cocktail.
Japanican, Kanagawa, Japan, +81 3 3865 5718; from $45 per person
Trolley tour of Green-Wood Cemetery, Brooklyn, New York
The trolley tours of the Green-Wood cemetery, recently granted National Historic Landmark status, are especially popular in the run up to Halloween.
Visitors see the graveside monument of Jim Creighton, baseball's first celebrity player, and visit the cemetery's beautiful chapel, a replica of Christopher Wren's Thomas Tower at Christ Church College in Oxford.
You can even down a cocktail in the cemetery's catacombs.
Green-wood, 500 25th St., Brooklyn, New York; +1 718 768 7300; from $15 per person
Weird Meat Tour, Shangai
If the thought of eating dog turns your stomach, this isn't your day out.
"Fly in my soup" jokes don't work here.
The weird meat tour takes participants on an exploration of Shanghai's food markets and back alley restaurants where they'll sample dragonfly, duck tongue and bumblebee.
Hidden City tours, Barcelona
They say locals make the best tour guides.
Barcelona tourist board takes that concept a step further by employing local homeless people to conduct tours of Spain's second largest city.
There are 3,000 homeless people in Barcelona, so there's no shortage of guides, who offer a unique perspective on the city.
Dearly Departed tours, Hollywood, California
The man behind Dearly Departed tours, Scott Michaels, reportedly became interested in death after attending a funeral when he was three years old.
Today, his morbid tours of Hollywood attract tourists from all over the world.
Current tours feature locations connected with the Manson family murders and hotels where John Belushi, Whitney Houston and Janis Joplin died.
Historic toilet tour, York, UK
York is one of Europe's oldest cities -- on this tour visitors get an insight into the bathroom habits of Vikings and Romans.
You'll get to know the bowels of the city.
A Victorian toilet and Viking cesspits are featured, as is the chance to examine pottery shards believed to have been used as "bottom scrapers."
Oh, the things you'll learn -- sponges soaked with vinegar and attached to sticks were used as toilet roll.
You also get the chance to try out a garderobe (medieval toilet) for yourself.
Yorkwalk; Fairway, Clifton, York, UK; +44 1904 622303; from $8 per person
Idaho Barn Tour, Idaho
Barns are part of the U.S. state of Idaho's cultural and physical landscape.
The Idaho Heritage Barn committee has created a free, self-guided tour of the state's most beautiful barns.
There are more than 100 to admire, including the Tovey Intermountain dairy barn, with its beautiful gambrel roof, and the Wright/Woodward raised barns favored by the Mormons.
Funky Chicken Coop Tour, Austin, Texas
Austin's Funky Chicken Coop Tour was set up by the Urban Poultry Association of Texas, with the aim of encouraging people living in urban areas to start breeding chickens.
The first tour took place six years ago, and today they include visits to spectacular chicken coops, including one containing a metal giraffe and another with chandeliers.
Randy Roy's Red Light Tours, Amsterdam
This tour teaches visitors about Amsterdam's red light district, its history and the men and women who work there.
As much a tourist attraction as anything else.
It provides the chance to enjoy a caffeine fix in the coffee shops favored by Mike Tyson and Quentin Tarantino, and illuminates the rules that protect those who work there and how the government monitors the area.
Corrupt tour, Prague, Czech Republic
Beneath Prague's beautiful architecture lies a darker side, one that the guides behind the successful Corrupt Tours are keen to expose.
Highlights include what guides refer to as Prague's "monuments of corruption" -- the enormous, heavily gated homes of controversial political lobbyists such as Roman Janousek (dubbed Lord Voldemort by the media), a hospital where having the right connections will help you jump the queue and an exclusive school where the right amount of cash can buy you a first class degree. Allegedly.