The Oscars presentation represents the peak of awards season. It is the height of glory and the height of fashion packed into one star-studded night. It is the one night that could turn a sweet, lesser-known actress into a bona fide Cinderella.

Of course, there are many reasons to watch the Academy Awards show (set for Sunday this year). The host is always charming. The speeches are always touching. And the couples are always fun to see. However, the best reason to watch the Oscars is the fashion. There is no other runway quite like the Oscars red carpet. Hollywood's most beautiful women decked out in the most glamorous clothing is surely not something to miss.

For designers, Oscars night can make or break a career. Celebrities have been bribed with everything from free clothes to facelifts to cold hard cash by designers who want their dresses shown. It is quite tempting. On Oscars night, designers get unparalleled exposure, watched by millions of eager eyes.

Stylists will typically choose between 40 and 80 gowns for his or her celebrity client to choose from for Oscars night. Many of these choices come from the latest fashion shows (e.g., the Paris Haute Couture event or New York Fashion Week).

However, designers can and will turn down even the most popular Oscar-nominated actresses.

Designers do turn celebrities down, absolutely, The Hollywood Reporter's Merle Ginsberg told the New York Post recently. There are two 'not skinny' actresses who are nominated for Academy Awards: Melissa McCarthy and Octavia Spencer -- check out the labels they've been wearing to awards shows: Badgley Mischka and Tadashi Shoji. They might look good, but they're not getting Chanel ... and women over 40 probably aren't getting Chanel.

It's not just the stylist's relationship with the fashion house that dictates what labels someone is offered, it's much more than that, Ginsberg told the Post. Even if you look at the difference between Cameron Diaz and Anne Hathaway in terms of what they wear ... you're more likely to see Anne in couture. She's more likely to be in a serious, Oscar-style movie ... Cameron might be in a hit movie, but she has a different image to designers.

If an actress wants a custom-made gown, she must contact a particular designer months in advance of the Oscars.

If you want a custom gown sketched by a designer with beading and embroidery, that can take many weeks to prepare, Marilyn Heston, head of MHA, an Los Angeles-based international company that pairs celebrities with designers and luxury brands, told The Hollywood Reporter.

However, custom-made gowns are not given out like candy. In fact, they are reserved for the most special leading ladies.

It's not an overnight deal to get a spectacular Oscar dress, Heston told the Reporter. Generally, these tailor-made dresses are only offered to nominees and presenters for the Globes and the Oscars. If a designer spends all that time and money on a gown, they want to make sure that it will end up in Vogue or Women's Wear Daily. This is not an artistic endeavor. The only reason a global designer is dressing an actress is to gain exposure that will raise awareness and increase sales.

Here is a look at some of the most memorable Oscars gowns of all time.