function nafrica(){
    document.getElementById('nafrica').style.display = 'block';
}

function safrica(){
    document.getElementById('safrica').style.display = 'block';
}

function namerica(){
    document.getElementById('namerica').style.display = 'block';
}

function samerica(){
    document.getElementById('samerica').style.display = 'block';
}

function europe(){
    document.getElementById('europe').style.display = 'block';
}

function asia(){
    document.getElementById('asia').style.display = 'block';
}

function clearImages(foo){
    document.getElementById(foo).style.display = 'none';
}