If we talk about famous marathons, probably the first one that comes to mind is the New York City Marathon, because it is the biggest marathon in the world (in 2013, 50,304 participants managed to finish it).
This marathon has been held since 1970, and has only failed once, when in 2012 Hurricane Sandy hit the coast of the eastern region of the United States. It is held on the first Sunday in November.
The initial route, created by Fred Lebow and Ted Corbitt, ran exclusively through Central Park, on a circuit that had to be repeated several times. Today it runs through the five boroughs that make up New York City. Starting on Staten Island, it takes runners to Brooklyn via the Verrazano Bridge, which is closed to traffic for the occasion. The route runs through Brooklyn for 18km until it reaches the Pulalski Bridge, located halfway across the race and at the Queens Gate. Manhattan is soon reached, as after only 4km more, it is accessed via the Queensboro Bridge, the climb to which is considered probably the most difficult part of the route.
The race then passes through the Bronx, Harlem and heads across 5th Avenue to Central Park, where the race ends in front of thousands of fans supporting all the runners.
Finishing the race is not so complicated, as the organization gives a time limit of 8 and a half hours.

The real difficulty lies in the inscription.
And if finishing in 8 hours and a half is "affordable", the real challenge is to be one of the registered runners. As it is the most important marathon in the world, every year thousands of amateurs try to participate. For the 2014 marathon, the organization offers five ways to register:
Running for charity
We will obtain guaranteed entrance. You will have to collect a sum of money to donate to the organization of your choice, which you can either pay or raise funds in any way you see fit.
Packages for travel agencies
Tour operators and travel agencies can assure us a place at the starting line. It is probably the most comfortable, but it can be a generous expense. A package that includes accommodation, flight, travel and our precious bib, but it is not an option available to all pockets.
Access by draw
We can opt to enter the lottery to get a bib. The cost to enter the lottery is $11, which is payable whether or not you are a "winner" of a bib. If you are a "winner" (note the quotation marks), your credit card will be charged $347, which will entitle you to receive the following.
There is another way to get guaranteed access, and that is if you have participated in the lottery for three years in a row, without having been awarded the precious bib, your entry will be guaranteed for the fourth year.
