Map sheet number 188 in the OS Explorer map series is ideal for discovering the upper section of the Wye Valley around Builth Wells. The Wye Valley Walk recreational path meanders alongside the river Wye offering exciting terrain to explore. Other highlights of the area include: Painscastle, Talgarth & Pwllgloyw. With this map you will receive a code for use on your i OS or Android smartphone or tablet. Find our more at Mobile Download FAQ. The OS Explorer map for Builth Wells is available in both the standard paper version & weatherproof ' Active' version.