The most significant historical site accessible from Mragowo is the Wolf's Lair (Wilczy Szaniec) at Gierłoż near Kętrzyn, about 50 kilometres northeast. This was Hitler's main eastern front headquarters from 1941 to 1944 — a vast complex of reinforced bunkers buried in forest, where the Wehrmacht command operated during some of the most critical years of the Second World War. It was here that the July 1944 assassination attempt on Hitler (Operation Valkyrie) took place. The bunkers were partly demolished before the German retreat in 1945 but remain in massive, overgrown fragments; walking through the ruins has a weight that is hard to shake. The site is open to visitors and has a small museum.
Mikołajki, about 18 kilometres east on the shore of Lake Śniardwy, is the most attractive town in the Masurian region — a sailing resort with a proper old market square, streets of 19th-century architecture, and direct access to Śniardwy, the largest lake in Poland. It makes a better base than Mragowo for anyone primarily interested in sailing or scenery. Ruciane-Nida to the south is the gateway to the Pisz Forest and the Krutynia River kayak trail. All three destinations can be reached by car in under an hour from Mragowo.