The Pantheon of the Heroes is Asuncion's most visited monument — a circular neo-classical dome modelled loosely on Les Invalides in Paris, sitting in the middle of the historic centre. Inside, the remains of Paraguay's most significant historical figures rest in marble tombs, flanked by an eternal flame and ceremonial guards who change on the hour.
The building is free to enter and takes about twenty minutes to walk through. The guard-change ceremony, when it happens, is worth waiting for — an elaborate, somewhat theatrical affair that draws a small crowd of locals and tourists alike. The surrounding plaza is shaded and has benches, making it a reasonable place to rest between other sights.