irgendwo

1. somewhere
2. anywhere (in one particular place)

in

• Prep

  1. [with dative] in, inside, within, at (inside a building)
  2. [with dative] in (pertaining to)
  3. [with dative] in, at, by (at the end of or during a period of time)
  4. [with accusative] into, to (going inside (of))

• Contraction
• Adj

der

• Article

  the

• Pron
• Pron
• Pron
• Pron

Menschenmenge

crowd, throng (of people)

sind

1. first-person plural present of sein
2. second-person polite present of sein
3. third-person plural present of sein

sie

1. she
2. it (when the object/article/thing/animal etc., referred to, is feminine [die])
3. he (when the grammatical gender of the noun being referred to and designating a male person, is feminine [die])

dann

1. then, after that
2. then, in that case

untergetaucht

past participle of untertauchen