A double supporting structure in painted or stainless steel looks great and holds more (400kg per square meter) than most modular stairs, says the company. The made-to-measure Metropol line mixes metal structure with transparent or satin-finish stratified glass treads for contemporary applications. Optional wood treads in natural, walnut, mahogany, or wenge add a touch of tradition. Rintal, 877.816.2113; www.modularstairs.com.