The world

en

1. in, at, on
2. in (a time)
3. in (a language)
4. used after some verbs and translated by various prepositions in English
5. in (in various expressions)

su

1. Apocopic form of suyo his, her, its, one's, their, your (formal)
2. Apocopic form of suyo his, her, its, one's, their, your (formal)
3. Apocopic form of suyo (“your”)

juventud

1. youth
2. a youth, young person

recorrió

third-person singular preterite indicative of recorrer

Europa

1. Europe (the portion of Eurasia west of the Urals, traditionally considered a continent in its own right, located north of Africa, west of Asia and east of the Atlantic Ocean)
2. Europa (large moon of Jupiter)
3. Europa (asteroid)
4. Europa (woman seduced by Zeus)

escribió

third-person singular preterite indicative of escribir

varios

1. masculine plural of vario
2. various, several

libros

plural of libro