Entry No. 7 — the Denver file — filed under: street art
RUMTUM UV-Reactive Mural
RiNo is wall-to-wall murals, but this RUMTUM piece has a second painting hiding inside it that daylight never shows. The artist worked UV-reactive elements into the design, so the concealed imagery only appears after dark under a blacklight, and basically nobody walks the murals carrying one. Show up at night with a cheap UV flashlight and the wall changes into something else entirely. It lives on a quieter stretch of Walnut, in the alley between 28th and 29th.
The move: Bring a small blacklight/UV flashlight and go after dark: walk the Walnut alley, find the RUMTUM wall, then kill the phone lights and watch the hidden imagery glow into view together.
📍 Before you go This sits on a quieter, semi-industrial stretch of Walnut at the edge of RiNo's denser mural core, so plan to park on the street or in one of the district's paid lots and walk the last few blocks in. RiNo is Denver's thickest concentration of murals, so build a broader wall-crawl around the visit and cap the evening at a Larimer-corridor brewery or eatery a short walk away. One real catch: these walls rotate, especially after the district's late-summer-into-fall mural festivals, so confirm this specific piece is still up before making a special trip. The alley backs onto working and residential property, so keep the noise down and be respectful late at night.
- 📍 RiNo (River North Art District)
- 💸 Free
- ⚡ Low-key
- 🌗 Outdoors
Where: RUMTUM mural, Walnut St alley between 28th and 29th, Denver (RiNo); near the 2555 Walnut St vicinity
Hours: Outdoor public mural, accessible anytime, but the hidden UV effect only works after dark, so go at night and bring your own blacklight. Murals can be repainted over time.
Plan a visit & invite your people →
Further reading: rinoartdistrict.org · denversam.com
last checked: 2026-06-07