Heritage Open Day: Built on the site of one of the largest Roman cities in Britain, Verulamium Museum is filled with ancient treasures and some of the finest mosaics outside of the Mediterranean. Visit for free as part of Heritage Open Days Bring the entire family and explore the wonders of Roman life, immerse yourself in recreated Roman rooms and admire the craftsmanship of the intricate large-scale mosaics on display. In its heyday, Verulamium had a population of about 5,000 people. The collections on display highlight the everyday life of its inhabitants. You can also see recent discoveries such as the Sandridge Hoard, a collection of 159 Roman gold coins.