Cannot get element placed above others

Here is the site

Whenever I hover over a link for the navigation, it appears behind the sl开发者_运维技巧ideshow. Why?

You need to add a

z-index: 1;

to

#slideshow ul {
    height: 320px;
    left: 10px;
    list-style: none outside none;
    overflow: hidden;
    position: absolute;
    top: 10px;
    width: 620px;
    margin: 0;
    padding: 0;
    z-index: 1;
}

and a

z-index: 1000;

to

.menu li {
    float: left;
    padding: 0px;
    z-index: 1000;
}

z-index specifies the stack order of an element.

An element with a greater stack order is placed in front of an element with a lower stack order.

You have to increase the z-index (currently set to 200) of the ul, to be higher than the z-index of the slideshow (currently set to 1000).