Instrument
Trombone
The only common orchestral instrument that changes pitch with a sliding tube instead of valves.
The trombone is the brass family's outlier: instead of valves rerouting air through extra tubing, a trombonist changes pitch by physically sliding a U-shaped section of tube in and out, lengthening or shortening the air column directly. That mechanism gives the trombone a genuinely continuous glide between pitches (a glissando) that valved brass instruments like the trumpet can't reproduce cleanly.
Historically, the trombone kept a strong association with sacred and ceremonial music (it was a mainstay of church and civic brass ensembles well before becoming a regular orchestral fixture), and composers have long used its combination of power and dignity for solemn or triumphant passages alike.
Where to start listening: the trombone-led "Dies irae" passages in various Requiem settings (including Mozart's and Verdi's) show the instrument's weightier, more solemn character.