Learn German: Wir versammeln uns heute, um ein großartiges Vorbild zu würdigen. - We gather today in order to honor a great role model.

The structure um ... zu specifically means "in order to." It tells us the purpose or goal of the gathering. A standard zu + infinitive just acts as the grammatical object of a previous verb, but whenever you want to express "for the purpose of doing something," you need to include the um.

Why is the reflexive pronoun uns needed in this sentence?

The verb versammeln literally means "to collect" or "to assemble [something/someone]." When a group of people comes together, they are technically gathering themselves, which requires the reflexive pronoun (sich versammeln). Without uns, a German speaker would wait for you to specify what outside objects or people you are gathering.

Why does großartiges end in -es?

It is describing the neuter noun das Vorbild in the accusative case. Since the indefinite article ein doesn't have an ending that reveals the noun's gender here, the adjective has to step up and take the strong neuter ending -es to do the job.

Würdigen is translated as "to honor" here. How does it differ from a word like ehren?