Yes they are parallel.
In case of parallelism, the main point is, ideas should be in parallel.
Here we are talking about a list of great achievements in human history.
And what are they?
1. The art of Michelangelo
2. the inventions of Edison
3. the plays of Shakespeare

Tetura is correct. This is a comparison question (similar to parallelism). The idea is that we can only compare things to things and people to people, but NOT people to thing.

For example:

CORRECT: The plays of Shakespeare are more famous than the plays of Marlowe.

Also CORRECT: The plays of Shakespeare are more famous than those of Marlowe.

Here we use a correct pronoun to take the place of "plays."

Also CORRECT: The plays of Shakespeare are more famous than Marlowe's.

Here the possessive indicates what is being compared.

INCORRECT: The plays of Shakespeare are more famous than Marlowe.

We need to compare the thing "plays" to the thing "plays." We cannot compare the "plays" (thing) to "Marlowe" (a person).

VivianKerr wrote:Tetura is correct. This is a comparison question (similar to parallelism). The idea is that we can only compare things to things and people to people, but NOT people to thing.

For example:

CORRECT: The plays of Shakespeare are more famous than the plays of Marlowe.

Also CORRECT: The plays of Shakespeare are more famous than those of Marlowe.

Here we use a correct pronoun to take the place of "plays."

Also CORRECT: The plays of Shakespeare are more famous than Marlowe's.

Here the possessive indicates what is being compared.

INCORRECT: The plays of Shakespeare are more famous than Marlowe.

We need to compare the thing "plays" to the thing "plays." We cannot compare the "plays" (thing) to "Marlowe" (a person).

HI vivian,
Thanks for your such a useful post regarding comparisions...but i still have one doubt...see the below example

With companies spending large parts of their advertising budgets online, the market for content such as feature articles and opinion essays created by professional writers, bloggers, and individual users, is expanding rapidly.

here all the 3 Nouns (in bold) are parallel..and all are plural. Now my question is if out of these 3 nouns suppose one is plural and other 2 are singular...in that case, do we consider the sentence parallel..in short is this sentence parallel???

With companies spending large parts of their advertising budgets online, the market for content such as feature articles and opinion essays created by professional writers, blogger, and individual users, is expanding rapidly.

In parallelism, i understand we make similar things parallel..such as adj. to adj etc..but in case of nouns do we consider their number also??? Please explain..

No, they don't need to be parallel in number. You can say baseball, hot dogs, and apple pie. (singular, plural, singular).

Jim@Grockit wrote:No, they don't need to be parallel in number. You can say baseball, hot dogs, and apple pie. (singular, plural, singular).

Thank you very much Jim...your post clear my confusion

Thanks again