Environmentalists in Vietnam are battling a national highway project which they say threatens endangered wildlife. Construction began in April on the Ho Chi Minh Highway, which is planned to run for more than 1,000 miles from near Hanoi in the north to Ho Chi Minh City in the south, following parts of the legendary Ho Chi Minh Trail. Five environmental groups, including the World Wildlife Fund, released a statement yesterday warning that the highway construction could harm 10 protected areas, including national parks and nature reserves, and threaten two critically endangered species of langurs, or monkeys, as well as tigers, elephants, and other animals.