The biggest fire in Moscow in a century destroyed the Manezh building in Moscows Red Square this week. The 187-year-old architectural treasure, located next to the Kremlin, was used for horseback riding in czarist times and more recently as an exhibition center. City officials investigating the blaze said there was no indication of arson or terrorism; they blamed faulty wiring. Many Muscovites were skeptical. Artist Vadim Konech, whose paintings were on exhibit in the Manezh, said bystanders watching the blaze discussed only two possibilities: Who set it on firean investor or the city? Moscow officials had long wanted to overhaul the Manezh, but had been thwarted by historic-preservation activists.