ekimae no hiroba no hunsui no mawari ni, kankou de kita hito ga takusan atumatte imasita.

This is a chain of nouns, where each の connects one noun to the next.

Break it down like this:

• 駅前 = in front of the station / station-front area
• 駅前の広場 = the plaza in front of the station
• 駅前の広場の噴水 = the fountain in the plaza in front of the station
• 駅前の広場の噴水の周り = the area around the fountain in the plaza in front of the station

So Japanese often builds location phrases from the inside outward like this.

A natural English unpacking is:

• around the fountain
• in the plaza
• in front of the station

All of that gets compressed into one noun chain in Japanese.

Yes, 駅前 literally means in front of the station, but in actual use it often refers to the general area around the front of the station, not just the exact spot directly in front.

So:

• 駅 = station
• 前 = front
• 駅前 = station-front area / area in front of the station

It is a very common compound word. You will often see it in things like:

• 駅前の店 = a shop near/in front of the station
• 駅前広場 = station-front plaza

周り means surroundings / around / the area around something.

In this sentence, に marks the place where the gathering happened:

• 噴水の周りに = around the fountain

With verbs like 集まる (to gather), に commonly marks the destination or location where people gather.

So:

• 公園に集まる = gather in/at the park
• 駅に集まる = gather at the station
• 噴水の周りに集まる = gather around the fountain

Even though English uses around, Japanese still uses に because it is marking the place of gathering.

Here, で shows the reason, purpose, or basis in a broad sense:

• 観光で来た人 = people who came for sightseeing / people who came as tourists

So the idea is that sightseeing is the reason they came.

This use of で can sometimes feel similar to because of, for, or on depending on context.

For example:

• 仕事で東京に来た = came to Tokyo for work
• 旅行で来た = came on a trip
• 観光で来た = came for sightseeing

This is a very natural expression.

Yes, 観光に来た人 is also possible, and it is very natural.

The difference is subtle:

• 観光に来た人 focuses more directly on coming in order to sightsee
• 観光で来た人 frames sightseeing more as the reason/background for coming

In many everyday contexts, the difference is small, and both can be translated as people who came for sightseeing.

Roughly speaking:

• 〜に来る = come to do something
• 〜で来る = come because of / for the purpose of / in connection with something

So both work, but they highlight the idea slightly differently.

Because Japanese puts modifying clauses before the noun they describe.

So:

• 来た人 = the person/people who came
• 観光で来た人 = the people who came for sightseeing

This is called a relative clause in English grammar terms.

Japanese does not need a word like who here. Instead of saying:

• people who came for sightseeing

Japanese simply says:

• 観光で来た人

Other examples:

• 日本に住んでいる人 = a person who lives in Japan
• 昨日会った人 = the person I met yesterday
• 本を読んでいる学生 = the student who is reading a book

Here, が marks 人 as the subject of 集まっていました.

• 観光で来た人がたくさん集まっていました = many people who had come for sightseeing were gathered / had gathered

Using が feels natural because this is introducing or identifying who it was that gathered.

If you used は, it would sound more like you were making those people the topic and then saying something about them, often with a contrastive nuance.

Very roughly:

• が = marks the subject, often new or focused information
• は = marks the topic, often something already being talked about

In this sentence, が is the normal choice.

In this sentence, たくさん works adverbially with the verb:

• 人がたくさん集まっていました = a lot of people were gathered / many people had gathered

So it describes the extent of the gathering.

You could also say:

• たくさんの人が集まっていました = many people were gathered

Both are natural, but there is a slight structural difference:

• たくさんの人 = many people
• 人がたくさん集まる = people gather in large numbers

So the original sentence emphasizes the action gathered in large numbers, not just the noun many people.

It can suggest either, depending on context.

Base verb:

• 集まる = to gather / to assemble

Form here:

• 集まっていました = polite past 〜ている form

The tricky part is that 〜ている can mean different things in Japanese:

1. ongoing action

   • people were gathering

2. resulting state

   • people had gathered / were gathered there

With 集まる, the second interpretation is often very natural. So this sentence can suggest that, at that time, there was already a crowd gathered around the fountain.

A natural English translation might be:

• A lot of people who had come for sightseeing were gathered around the fountain in the plaza in front of the station.

or

• A lot of people visiting for sightseeing were gathering around the fountain...

Both are possible, but were gathered / had gathered often fits well.

It is a noun.

• 周り = surroundings / area around

That is why it can take の before it and particles after it:

• 噴水の周り = the area around the fountain
• 噴水の周りに = around the fountain
• 家の周りを歩く = walk around the house

Japanese often uses location nouns like this:

• 上 = above/on top
• 下 = below/under
• 前 = front/before
• 後ろ = behind
• 中 = inside
• 周り = around

They behave like nouns, even though in English we often translate them like prepositions.

A good way to chunk it is:

• 駅前の広場の
• 噴水の周りに、
• 観光で来た人が
• たくさん集まっていました。

Or more structurally:

• [駅前の広場の噴水の周りに]
• [観光で来た人が]
• [たくさん集まっていました]

That gives you:

1. location: around the fountain in the plaza in front of the station
2. subject: people who came for sightseeing
3. predicate: had gathered / were gathered in large numbers

This kind of chunking makes long noun chains much easier to understand.