A Wonder Victory can be achieved by attaining certain advantage in Wonder Points (default 8). A team that exceeds all other teams by this amount must defend their Wonders -- and prevent enemies from building their own -- for the duration of the Wonder Victory timer. If the team retains the required advantage in Wonder Points for the entire duration of the timer, they win the game.
Wonder Victories can be disabled in game rules, or the required number of points can be changed. In Conquer the World campaigns, Wonder Points are always disabled and Wonder Victories are not possible.