Monumental (adjective)

1. Very large and impressive, especially as a work of architecture or sculpture.
2. Of great historical or cultural significance.

Origin:

Late 16th century: from french monumental or latin monumentalis, from monumentum (see monument).

Examples:

1. The monument was a monumental structure.
2. The statue was a monumental work of art.
3. The building was a monumental achievement in architecture.
4. The event was a monumental occurrence in history.
5. The achievement was a monumental accomplishment.