Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
German submarine U-21 (1936)
Table title:
Summary of raiding history
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > Nationality </th><th colspan=1 rowspan=1 > Tonnage </th><th colspan=1 rowspan=1 > Fate </th></tr>
<tr> <td colspan=1 rowspan=1 > 21 November 1939 </td><td colspan=1 rowspan=1 > HMS Belfast </td><td colspan=1 rowspan=1 > Royal Navy </td><td colspan=1 rowspan=1 > 11,500 </td><td colspan=1 rowspan=1 > Damaged (mine) </td></tr>
<tr> <td colspan=1 rowspan=1 > 1 December 1939 </td><td colspan=1 rowspan=1 > Mercator </td><td colspan=1 rowspan=1 > Finland </td><td colspan=1 rowspan=1 > 4,620 </td><td colspan=1 rowspan=1 > Sunk </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 21 December 1939 </td><td class="highlighted"  colspan=1 rowspan=1 > Carl Henckel </td><td class="highlighted"  colspan=1 rowspan=1 > Sweden </td><td colspan=1 rowspan=1 > 1,352 </td><td class="highlighted"  colspan=1 rowspan=1 > Sunk </td></tr>
<tr> <td colspan=1 rowspan=1 > 21 December 1939 </td><td colspan=1 rowspan=1 > HMS Bayonet </td><td colspan=1 rowspan=1 > Royal Navy </td><td colspan=1 rowspan=1 > 605 </td><td colspan=1 rowspan=1 > Sunk (mine) </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 21 December 1939 </td><td class="highlighted"  colspan=1 rowspan=1 > Mars </td><td class="highlighted"  colspan=1 rowspan=1 > Sweden </td><td colspan=1 rowspan=1 > 1,475 </td><td class="highlighted"  colspan=1 rowspan=1 > Sunk </td></tr>
<tr> <td colspan=1 rowspan=1 > 31 January 1940 </td><td colspan=1 rowspan=1 > Vidar </td><td colspan=1 rowspan=1 > Denmark </td><td colspan=1 rowspan=1 > 1,353 </td><td colspan=1 rowspan=1 > Sunk </td></tr>
<tr> <td colspan=1 rowspan=1 > 24 February 1940 </td><td colspan=1 rowspan=1 > Royal Archer </td><td colspan=1 rowspan=1 > United Kingdom </td><td colspan=1 rowspan=1 > 2,266 </td><td colspan=1 rowspan=1 > Sunk (mine) </td></tr>
</table>
Question:
Which Swedish ships did U-21 sink?
Answer:
German submarine U-21 sank Mars and Carl Henckel both from Sweden on 21 December 1939.