La majestad del paisaje parece grandiosa.

Because majestad is a feminine noun in Spanish, even though it ends in -dad, not -a. In fact, many nouns ending in -dad are feminine:

• la ciudad
• la verdad
• la libertad
• la majestad

So the article must be la.

Del is the contraction of de + el.

• de = of
• el = the
• de el → del

So la majestad del paisaje means the majesty of the landscape.

This contraction is required in normal Spanish whenever de is followed by the masculine singular article el.

Parece comes from parecer, which means to seem or to appear.

So:

• es grandiosa = is grand / is magnificent
• parece grandiosa = seems grand / appears magnificent

Spanish uses parecer when something gives an impression, rather than stating it as a direct fact.

Because it agrees with majestad, which is feminine.

In Spanish, adjectives usually agree in gender and number with the noun they describe:

• masculine singular: grandioso
• feminine singular: grandiosa
• masculine plural: grandiosos
• feminine plural: grandiosas

Here, the thing that seems grand is la majestad, not el paisaje, so the adjective is feminine: grandiosa.

It describes majestad.

The structure is:

• La majestad del paisaje = the majesty of the landscape
• parece grandiosa = seems magnificent

The main noun of the subject is majestad, and del paisaje only tells you whose majesty it is. That is why the adjective agrees with majestad, not with paisaje.

This is the most neutral Spanish word order:

subject + verb + adjective/complement

• La majestad del paisaje = subject
• parece = verb
• grandiosa = complement

Spanish does allow other word orders for emphasis, but this version sounds natural and standard.

Yes, but it means something slightly different.

• La majestad del paisaje parece grandiosa focuses on the majesty of the landscape.
• El paisaje parece grandioso focuses directly on the landscape itself seeming grand.

Both are correct, but the first is more literary or elevated.

It is a real and correct word, but it is somewhat formal, literary, or elevated in this kind of sentence.

In everyday speech, people might be more likely to say things like:

• El paisaje es impresionante
• El paisaje es majestuoso
• Tiene una belleza increíble

So majestad is natural, but it has a more poetic tone here.

Both are positive and elevated, but they are not exactly the same.

• grandiosa = grand, magnificent, impressive in scale or effect
• majestuosa = majestic, stately, dignified, noble-looking

So:

• parece grandiosa emphasizes grandeur
• parece majestuosa would emphasize majesty more directly

Both could work depending on the nuance you want.

Yes. That is very common.

A common pattern in Spanish is:

parecer + adjective

Examples:

• Parece interesante.
• La idea parece buena.
• El edificio parece antiguo.
• La majestad del paisaje parece grandiosa.

This works much like seem + adjective in English.

There actually is an article there: el. It is just combined with de to make del.

So:

• de el paisaje → del paisaje

You still have the article the inside that phrase; it is just contracted.

Yes, that is possible, but it changes the structure and tone.

• La majestad del paisaje parece grandiosa = the majesty of the landscape seems grand
• La grandiosa majestad del paisaje = the grand majesty of the landscape

Putting the adjective before the noun often sounds more literary, expressive, or subjective. After the noun is usually more neutral and descriptive.