Copying a range of column using a loop

Hi I want to copy all the columns of a worksheet in to another worksheet one below the another.

                                  Sheet A 

Column          A            B             C  ....................BL

             ValueA        ValueB       ValueC..................ValueBL
             ValueA2       ValueB2      ValueC2.................ValueBL2
                 .             .            .                        .
                 .             .            .                        .
             ValueA10       ValueB10     ValueC10...............ValueBL10

                                Target Sheet 

            Value A
               .
               .
            Value A10
            Value B
               . 
               .
            Value B10
            Value C
               .
               .
            Value C10

and so on. Basically each column has multiple values(rows) and there are hundreds of column. I want to copy all the columns one below the another. This will require a loop , but I don't understand as how to use it. Because

set ws1 As SheetA
set ws2 As Target  
Lastcol= ......
Lastrow=......
For i=1 to Lastcol
    ws1.Range("?" & lastrow).copy  ws2.Range("a65536").End(xlUP).Offset(1,0)
Next i

I am not getting as what to put instead of "?". Appreciate any help. Thanks.