Learn Hardcore Spanish (Spain): En la guía explican qué barrios son más tranquilos y cuáles son muy turísticos. - In the guide they explain which neighborhoods are quieter and which are very touristy.

Explican is 3rd person plural (they explain).
The implied subject here is they, usually understood as the authors or the people who wrote/created the guide.
So En la guía explican… literally feels like: “In the guide, they explain…”.
Spanish doesn’t need to say Ellos explican unless you want to emphasize who they are.

Could I say La guía explica qué barrios… instead of En la guía explican…? Is there a difference?

Yes, you can say La guía explica qué barrios son más tranquilos…, and it’s correct.

La guía explica… treats la guía as the subject (the guide “explains”).
En la guía explican… treats they (the writers, editors, etc.) as the subject and en la guía just tells you where they explain it.
Both are natural in Spanish; the choice is mostly stylistic.
There’s also a very common impersonal version: En la guía se explica qué barrios… = “In the guide, it is explained which neighbourhoods…”, sounding a bit more neutral/impersonal.

Why do qué and cuáles have accents here?

The accents show that qué and cuáles are interrogative (or exclamative) words, even inside an indirect question.

Explican qué barrios son… = “They explain which neighbourhoods are…”
Explican cuáles son muy turísticos = “They explain which (ones) are very touristy.”
In indirect questions, Spanish still writes the accent:
- No sé qué quiere. – “I don’t know what he wants.”
- Dime cuáles prefieres. – “Tell me which ones you prefer.”
Without the accent (que, cuales), they would usually be conjunctions or relative pronouns, not question words.

What’s the difference between qué barrios and cuáles here? Why not use qué both times?

The pattern is:

qué barrios = which neighbourhoods (question word + noun)
cuáles = which ones (question word standing alone, replacing a known noun)

In the sentence:

qué barrios son más tranquilos – “which neighbourhoods are quieter”
y cuáles son muy turísticos – “and which (ones) are very touristy”

The noun barrios has already appeared, so Spanish sounds very natural using cuáles alone the second time, instead of repeating qué barrios.

You could say y qué barrios son muy turísticos, but it’s a bit heavier and more repetitive.

Why is it son and not the subjunctive sean in qué barrios son más tranquilos?

The indicative son is used because the guide is stating information, not expressing doubt, wish, or a non-real situation.

Verbs like explicar (to explain) typically introduce content that is treated as factual in the speaker’s mind, so Spanish uses indicative:
- Explican qué barrios son tranquilos.
- Dijo qué hoteles están abiertos.
You’d expect subjunctive with verbs or expressions of wish, doubt, possibility, emotion, etc., for example:
- Busco barrios que sean tranquilos. – “I’m looking for neighbourhoods that are (might be) quiet.”

What exactly does en la guía mean? Why en and not en el or something like sobre la guía?

En la guía literally means “in the guide” (inside that book or document).

en = “in/on” depending on context; here it’s like “in a book / in a guide”.
la guía is definite: “the guide” (a specific guide you’ve mentioned or that both speakers know about).
You wouldn’t say en el guía here because el guía is normally a person (the guide as a person), while la guía is the guidebook or written guide.
sobre la guía would mean “about the guide (itself)”, which is a different meaning.

Why is it la guía and not el guía? I thought guía was masculine.

Guía can be masculine or feminine, depending on the meaning:

el guía = the (male) guide as a person (tour guide, leader, etc.).
la guía =
- the (female) guide as a person, or
- a guidebook / written guide / manual (always feminine for the object).

In this sentence, we’re talking about something you read that explains which neighbourhoods are quiet, so it’s clearly a guidebook → la guía.

Why are tranquilos and turísticos placed after barrios? Could they go before?

The normal, neutral position for most adjectives in Spanish is after the noun:

barrios tranquilos – quiet neighbourhoods
barrios turísticos – touristy neighbourhoods

You can put some adjectives before the noun, but it often adds a special nuance (more emotional, subjective, or poetic), or it simply sounds less natural in everyday speech.

tranquilos barrios would sound odd here; you’d more likely see it in a literary context, if at all.
So, barrios tranquilos and barrios turísticos are the standard, natural orders.

What’s the difference between más tranquilos and muy turísticos? Why use más with one and muy with the other?

Más and muy do different jobs:

más tranquilos = “quieter / more quiet” → a comparative idea (more X than others).
muy turísticos = “very touristy” → just intensifies the quality, not a comparison.

So the guide is:

comparing some neighbourhoods to others in terms of quietness (más tranquilos)
and simply saying that some are strongly touristy (muy turísticos), not necessarily comparing how touristy they are.

You could say muy tranquilos as well (very quiet), or más turísticos (more touristy), depending on what nuance you want.

Could I drop the second son and say …qué barrios son más tranquilos y cuáles muy turísticos?

Yes, that’s grammatically possible in Spanish.

When you have the same verb repeated in coordinated parts, you can omit it in the second part:
- Son más tranquilos y (son) muy turísticos.
So …qué barrios son más tranquilos y cuáles muy turísticos would be understood as “…which neighbourhoods are quieter and which (ones) are very touristy.”
However, many speakers will keep the second son in careful or written language because it sounds a bit clearer and more balanced: y cuáles son muy turísticos.

What exactly does barrios mean in Spain? Is it just “neighbourhoods”?

In Spain, barrio is basically a neighbourhood / district within a town or city.

It’s an administrative or commonly recognized area: el barrio de Salamanca, el barrio gótico, etc.
Often it has a particular atmosphere or reputation (quiet, trendy, touristy, residential…).
In many contexts, barrio(s) can indeed be translated as “neighbourhood(s)”, though in some Latin American varieties barrio can also carry social or economic connotations that depend on the country.

Is explican qué barrios son… considered a question in Spanish? It doesn’t have question marks.

No, it’s not a direct question; it’s an indirect question (a “that”-type clause in English).

Qué barrios son más tranquilos on its own, with ¿…?, would be a direct question:
- ¿Qué barrios son más tranquilos?
But in En la guía explican qué barrios son más tranquilos…, that whole part is just the content of the verb explican:
- They explain [which neighbourhoods are quieter].
Indirect questions in Spanish do not take question marks; only direct questions do.