<ul id="dropdown3">
   <li>
     <a href="#">AL East     </a>
     <ul>
       <li>
         <a href="#">Baltimore Orioles         </a>
       </li>
       <li>
         <a href="#">Boston Red Sox         </a>
       </li>
       <li>
         <a href="#">New York Yankees         </a>
       </li>
       <li>
         <a href="#">Tampa Bay Rays         </a>
       </li>
       <li>
         <a href="#">Toronto Blue Jays         </a>
       </li>     </ul>
   </li>
   <li>
     <a href="#">AL Central     </a>
     <ul>
       <li>
         <a href="#">Chicago White Sox         </a>
       </li>
       <li>
         <a href="#">Cleveland Indians         </a>
       </li>
       <li>
         <a href="#">Detroit Tigers         </a>
       </li>
       <li>
         <a href="#">Kansas City Royals         </a>
       </li>
       <li>
         <a href="#">Minnesota Twins         </a>
       </li>     </ul>
   </li>
   <li>
     <a href="#">AL West     </a>
     <ul>
       <li>
         <a href="#">Houston Astros         </a>
       </li>
       <li>
         <a href="#">Los Angeles Angels         </a>
       </li>
       <li>
         <a href="#">Oakland Athletics         </a>
       </li>
       <li>
         <a href="#">Seattle Mariners         </a>
       </li>
       <li>
         <a href="#">Texas Rangers         </a>
       </li>     </ul>
   </li> </ul>

In style element (<style>) within head element:

ul {
  padding: 0;
  margin: 0;
  list-style: none;
  }
li {
  position: relative;
  width: 15em;
}
li ul {
  display: none;
  position: absolute;
  top: 1.7em;
  left: 0;
}
li > ul {
  top: auto;
  left: auto;
}
li:hover ul { display: block; }

#dropdown3 li ul {
  margin-left: 15em;
  margin-top: -1.8em;
}
#dropdown3  li {
  border: thin solid navy;
  font-family: calibri,verdana,tahoma,helvetica,sans-serif;
  background-color: #ccf;
  }
#dropdown3 ul li { background-color: #eef; }
#dropdown3 a {display:block; padding: 0.25em;}
#dropdown3 a:link,
#dropdown3 a:visited,
#dropdown3 a:hover,
#dropdown3 a:active
  { text-decoration: none; font-weight: bold; }
#dropdown3 a:hover { background-color: navy; color: #ccf; }