Después del viaje, todos dijimos que el norte, el sur, el este y el oeste de la península tienen algo especial.

Because de + el normally contracts to del in Spanish.

• después de el viaje → incorrect
• después del viaje → correct

This contraction happens very regularly:

• al = a + el
• del = de + el

One important exception: you do not contract when el is part of a proper name, such as de El Escorial.

Dijimos is the preterite form of decir for nosotros:

• yo dije
• tú dijiste
• él/ella dijo
• nosotros dijimos

The preterite is used because the sentence refers to a completed action in the past: after the trip, everyone said this.

So dijimos means we said.

Because todos here includes the speaker.

• todos dijimos = we all said
• todos dijeron = they all said

Even though todos can mean everyone or all of us, the verb form shows whether the speaker is included. Since the verb is dijimos, the meaning is all of us said.

Que introduces the clause that reports what was said. It means that.

• dijimos que... = we said that...

In English, that is often optional:

• We said that the north...
• We said the north...

In Spanish, que is normally required in this kind of sentence.

Here, the compass points are being used as nouns, not as adverbs.

• el norte = the north
• el sur = the south
• el este = the east
• el oeste = the west

When they refer to regions, zones, or directions as nouns, Spanish usually uses the definite article.

Compare:

• El norte de la península es verde.
  = The north of the peninsula is green.
• Vamos al norte.
  = We’re going north / to the north.
• El sol sale por el este.
  = The sun rises in the east.

Because the subject is a list of four things:

• el norte
• el sur
• el este
• el oeste

Together, they make a plural subject, so the verb must be plural:

• tienen = they have

If there were only one subject, it would be singular:

• El norte de la península tiene algo especial.

This is a very common and important question.

Spanish often keeps the present tense in the subordinate clause if the speaker still sees the statement as true now.

So:

• Después del viaje, todos dijimos que... tienen algo especial.

means that after the trip, people said this, and the speaker still presents it as a current truth: those regions have something special.

If the speaker wanted to present it as just a past viewpoint, tenían could also be possible in some contexts:

• ...dijimos que... tenían algo especial.

That sounds more like: that was what we said/thought then.

So the present tienen is not a mistake. It suggests the idea is still valid.

Because algo is the normal and much more natural way to say something in Spanish.

• algo especial = something special

Alguna cosa is possible in some contexts, but it is less common and often less natural here.

Also, algo can be followed directly by an adjective:

• algo bueno = something good
• algo raro = something strange
• algo especial = something special

This is a standard pattern.

It modifies the whole series of compass points:

• el norte de la península
• el sur de la península
• el este de la península
• el oeste de la península

Spanish often avoids repeating the same phrase after every item in a list when the meaning is clear.

So instead of saying:

• el norte de la península, el sur de la península, el este de la península y el oeste de la península

the sentence uses the shorter and more natural version:

• el norte, el sur, el este y el oeste de la península

In a Spain context, la península often refers to the Iberian Peninsula, or sometimes more loosely to mainland Spain depending on context.

So a Spanish speaker from Spain may naturally understand this as referring to the main geographic peninsula associated with Spain.

Context matters, though. Grammatically, la península just means the peninsula.

Yes, but usually only when they are functioning differently.

With articles, they are nouns:

• el norte
• el sur

Without articles, they often behave more like adverbs or fixed directional expressions:

• Vamos norte is not normal standard Spanish.
• Vamos al norte is normal.
• Mira hacia el norte is normal.

You may also see them in compound adjectives or place descriptions:

• la costa norte
• la zona sur

But in this sentence they clearly act as nouns, so the articles are expected.

Because decir que normally takes the indicative when you are reporting a statement.

• Dijimos que tienen algo especial.

This simply reports what was said.

The subjunctive would appear in different structures, especially with doubt, denial, emotion, or influence. For example:

• No dijimos que tuvieran algo especial.
• Dudo que tengan algo especial.

But after a straightforward statement like dijimos que, the indicative is the normal choice.

The sentence is structured like this:

• Después del viaje = time expression
• todos = subject
• dijimos = main verb
• que... = reported clause
• el norte, el sur, el este y el oeste de la península = subject of the reported clause
• tienen = verb of the reported clause
• algo especial = object/complement

So the full pattern is:

After the trip + we all said + that + the north, south, east and west of the peninsula + have + something special

This is a very normal Spanish sentence pattern.

A few helpful points:

• dijimos: stress on -ji-? No — the stress is on -ji-'s syllable only if marked, but here the natural stress is di-JI-mos.
• península: the written accent shows the stress clearly: pe-NÍN-su-la
• oeste: usually pronounced roughly o-ES-te
• este: ES-te

Also:

• the j in dijimos is the strong Spanish sound, like the ch in Scottish loch or German Bach, not an English j
• v and b are pronounced very similarly in most Spanish accents, so viaje sounds with a b/v sound closer to Spanish b

A rough pronunciation of the whole sentence is:

des-PWÉS del BYA-he, TO-dos di-JI-mos ke el NOR-te, el SUR, el ES-te i el o-ES-te de la pe-NÍN-su-la TYE-nen AL-go es-pe-SYAL

That is only approximate, but it can help with stress.