#map{
  position: relative;
  display: block;
  width: 100%;
  height: 520px;
  margin: 0 auto;
  margin-bottom:0px;
}
.overlay{
  display:block;
  text-align:center;
  height:111px;
  width:100px;
  background:transparent url(../images/marker.png)no-repeat center;
}
.overlay_arrow{
  left:50%;
  margin-left:-16px;
  width:0;
  height:0;
  position:absolute;
}
.overlay_arrow.above{
  bottom:-13px;
  border-left:16px solid transparent;
  border-right:16px solid transparent;
  border-top:16px solid #000;
}
.overlay_arrow.below{
  top:-15px;
  border-left:16px solid transparent;
  border-right:16px solid transparent;
  border-bottom:16px solid #000;
}