Entry No. 39 — the Boulder file — filed under: mosaic
The Clarifier Project
A 1950s cement wastewater treatment tank in Lyons got 60,000 hand-painted tiles pressed into its 96-foot concrete circumference by 325 volunteers over eleven years — and it still isn't done messing with you, because GPS can't reliably find it. Walk the full ring and you'll pick out four seasons rendered in Lyons redstone trees, thirteen Front Range bird species, zodiac symbols, and ceramic leaves made by local kids, all grouted together with 800 pounds of grout and finished two years after the 2013 flood nearly ended the whole thing. The park sits right along the St. Vrain, which makes the flood backstory land differently when you're standing inside it.
The move: Drive up to Lyons, park near Main Street, then follow the river path until you find the tank and walk the full 360° ring together.
📍 Before you go The tank sits in a riverside park; GPS navigation is unreliable — park near Main Street and walk toward the St. Vrain River. Terrain is flat gravel path. No gate or fee.
- 📍 Lyons
- 💸 $$
- ⚡ Up for anything
- 🌗 Indoors
Where: 39 E. Main St., Lyons, CO
Hours: Added 2026-06-21 — confirm current hours before you go.
⚠ Seasonal or scheduled — always check before you go.
Plan a visit & invite your people →
last checked: 2026-06-21