The enthalpies of formation (Delta H-f degrees(g)) and the strain energies (E(str)) have been determined from combustion calorimetry for [1.1.1.1]pagodane 1 (47.9; 95.5 kcal/mol), its 4,9-bis(methoxycarbonyl) derivative 3 (-107.3; 95.5 kcal/mol) and the 1,6-bis(methoxycarbonyl)dodecahedrane 4 (-151.8; 61.4 kcal/mol). On the basis of these measurements Delta H-f degrees(g) = 22.4 +/- 1 kcal/mol (standard deviation) and E(str) = 61.4 +/- 1 kcal/mol are reliable estimates for parent (CH)(20) dodecahedrane 2, an ''evergreen'' for computational activities, in good agreement with the MM2 predictions.