Table in table, but not in tr-td.
 the outter table is ignored.
  
   caption of table1.
  
  | first cell in table1 | second cell in table1 | 
  | third cell in table1 | fourth cell in table1 | 
| This is the first cell in table2. | 
NOTE, even no line break here! 
Caption of outer table is ignored.
Data of outer table is treated as text.