Travertine forms from geothermal springs and is often linked to siliceous systems that form siliceous sinter. Macrophytes, bryophytes, algae, cyanobacteria, and other organisms often colonise the surface of travertine and are preserved, giving travertine its distinctive porosity.
Travertine is often used as a building material. The Romans mined deposits of travertine for building temples, aqueducts, monuments, bath complexes, and amphitheaters such as the Colosseum, the largest building in the world constructed mostly of travertine.
Other notable buildings using travertine extensively include the Sacré-Cœur Basilica in Paris, the 20th-century Getty Center in Los Angeles, California, and Shell-Haus in Berlin. The travertine used in the Getty Center and Shell-Haus constructions was imported from Tivoli and Guidonia.
Travertine is one of several natural stones that are used for paving patios and garden paths. It is sometimes known as travertine limestone or travertine marble; these are the same stone, although travertine is classified properly as a type of limestone, not marble. The stone is characterised by pitted holes and troughs in its surface. Although these troughs occur naturally, they suggest signs of considerable wear and tear over time. It can also be polished to a smooth, shiny finish, and comes in a variety of colors from grey to coral-red. Travertine is most commonly available in tile sizes for floor installations.
Travertine is one of the most frequently used stones in modern architecture. It is commonly used for façades, wall cladding, and flooring. The lobby walls of the modernist Willis Tower (1970) (formerly Sears Tower) in Chicago are made of travertine. Architect Welton Becket frequently incorporated travertine into many of his projects. The first floor of the Becket-designed UCLA Medical Center has thick travertine walls. Architect Ludwig Mies van der Rohe used travertine in several of his major works, including the Toronto-Dominion Centre, S.R. Crown Hall and the Farnsworth House.