• On March 9, 1975, work began on the Trans-Alaska Pipeline System. One of the biggest challenges facing engineers was permafrost—permanently frozen ground. Instead of burying the entire pipeline, about half of it had to be built above ground, so that the hot oil gushing through the pipe would not melt the permafrost. The pipeline took a little longer than two years to complete.

    The Trans-Alaska Pipeline System transports oil from Alaska’s North Slope to Valdez, the northernmost ice-free port in North America. The pipeline spans three mountain ranges, hundreds of rivers and streams, and includes more than 550 crossing areas for caribou, moose, and other wildlife

  • Term Part of Speech Definition Encyclopedic Entry
    engineer Noun

    person who plans the building of things, such as structures (construction engineer) or substances (chemical engineer).

    mountain range Noun

    series or chain of mountains that are close together.

    oil Noun

    fossil fuel formed from the remains of marine plants and animals. Also known as petroleum or crude oil.

    permafrost Noun

    permanently frozen layer of the Earth's surface.

    Encyclopedic Entry: permafrost
    pipeline Noun

    series of pipes used to transport liquids or gases over long distances.

    port Noun

    place on a body of water where ships can tie up or dock and load and unload cargo.

    Encyclopedic Entry: port
    transport Verb

    to move material from one place to another.

    wildlife Noun

    organisms living in a natural environment.