#gallery a span {
display: none;
}

#gallery a:hover span {
   display: block;
   position: absolute;
   top: 470px; 
   left: 580px;
   z-index: 100;
   background: none;
   font: bold 18px Times New Roman, Times, Georgia, serif;
   text-align: center;
   text-decoration: underline;
}