A weeklong celebration of commerce is underway in one of the world’s last communist countries, with hundreds of international corporations, including some big U.S. firms, flocking to Havana to try to do business with a government basking in expectations of growth set off by detente with Washington.

The Havana International Fair has long been among the stranger events in the world of international business: a trade fair in a cash-starved country that’s embargoed by the world’s most powerful nation and views markets with deep suspicion. For years, Cuban bureaucrats, foreign diplomats and businessmen gamely trooped through the halls of the Pabexpo fairgrounds on the outskirts of Havana, eyeing stalls stocked with such products as Spanish canned vegetables and dutifully attending government presentations on opportunities for investments in state-controlled pig farms and nickel mines.