Question: Finland won the first Eurovision Dance Contest in 2007, in 2008, Finland were represented by singer and actress Maria Lund, and dancer Mikko Ahti, danced a Tango,a Tango is a partner dance, that originated in the 1880s, along which location, the natural border between Argentina and Uruguay?

Context paragraphs:
Switzerland in the Eurovision Dance Contest: Switzerland took part in the first Eurovision Dance Contest in 2007.  Denise Biellmann and Sven Ninnemann were chosen as the first Swiss entrants.  The dances they performed at the contest were Paso Doble and Swing.  They are the only couple that have got zero points in the contest.  Switzerland did not take part in 2008.  The Third Eurovision Dance Contest has been cancelled indefinitely.

Tango: Tango is a partner dance that originated in the 1880s along the River Plata, the natural border between Argentina and Uruguay, and soon spread to the rest of the world.

Sweden in the Eurovision Dance Contest: Sweden took part in the first Eurovision Dance Contest in 2007.  Representing the country were Martin Lidberg, a professional wrestler and Cecilia Ehrling, a ballroom dancer.  The couple were chosen after winning the Swedish version of "Strictly Come Dancing".  The dances they performed at the contest were Paso Doble and Disco Fusion.  Sweden came fourteenth after receiving 23 points from 6 countries.  Sweden took part in 2008.  Sweden is one of only two countries never to come in the top 10, the other being the Netherlands.  The Third Eurovision Dance Contest has been cancelled indefinitely.

Ukraine in the Eurovision Dance Contest: Ukraine took part in the first Eurovision Dance Contest in 2007.  Representing the country were Yulia Okropiridze, a student of Kyiv National University of Culture and Arts, and Illya Sydorenko, a professional in ballroom choreography.  The dances they performed on the night were Quickstep and Showdance.  Ukraine came second after receiving 121 points from all other countries.  Ukraine is arguably the most successful country to date, with two top 3 positions, despite not winning yet.  Lilia Podkopayeva and Kirilo Hitrov represented the country in the 2008 contest.  The Third Eurovision Dance Contest has been cancelled indefinitely.

Finland in the Eurovision Dance Contest: Finland won the first Eurovision Dance Contest in 2007.  Jussi Väänänen and Katja Koukkula were chosen to represent the country on 25 August 2007 in a national preselection.  Finland was the last country to decide whom to send to the contest, the contest taking place only a week after the selection process.  The couple performed a Rumba and Paso Doble.  Finland won after scoring 132 points.  All other countries awarded Finland points, three of which gave 12 points.  In 2008, Finland were represented by singer and actress Maria Lund and dancer Mikko Ahti & who danced a Tango routine.

Eurovision Dance Contest 2007: The Eurovision Dance Contest 2007 was the 1st Eurovision Dance Contest a dance entertainment co-production between the European Broadcasting Union (EBU) and the BBC.  The first ever pan-European dance competition was held on 1 September 2007 in London, United Kingdom with the participation of 16 countries.  Viewers cast their votes by telephone and SMS text message voting on each couple's two dances – the first being ballroom or Latin with the second being freestyle, with a "national" flavour.  Comedian Graham Norton and Claudia Winkleman presented the 2007 contest from the BBC Television Centre in London.

Portugal in the Eurovision Dance Contest: Portugal took part in the first Eurovision Dance Contest in 2007.  Representing the country were Sónia Araújo, a TV host and Ricardo Silva, a ballroom dancer.  The couple were chosen after winning the second Portuguese version of "Strictly Come Dancing" ("Dança Comigo", in Portuguese).  The dances they performed at the contest were Jive and Tango.  Portugal came joint fifth after receiving 74 points from 12 countries.  It was their first top five finish in any Eurovision contest.

Azerbaijan in the Eurovision Dance Contest: Azerbaijan took part for the first time in the Eurovision Dance Contest in 2008 in Glasgow, United Kingdom.  Azerbaijan came in 5th place with 106 points, getting two 12 points from Lithuania and Poland.  The EBU confirmed that the Eurovision Dance Contest 2010 will be held in Baku, Azerbaijan at the Heydar Aliev Sports and Concert Complex in 2010.

United Kingdom in the Eurovision Dance Contest: The United Kingdom was the host country for the inaugural Eurovision Dance Contest in 2007 and also hosted the 2008 competition.  The Third Eurovision Dance Contest has been cancelled indefinitely.

Russia in the Eurovision Dance Contest: Russia took part in the first Eurovision Dance Contest in 2007.  The couple chosen to represent the country were Vladislav Borodinov and Maria Sittel.  The dances they performed at the contest were Rumba and Paso Doble.  Russia came seventh after receiving 72 points from 11 countries.  In 2008 they were represented by Tatiana Navka and Alexander Litvinenko who danced a fusion of Cha-Cha, Samba, Rumba, Paso Doble and Russian Folk Dance.  The Third Eurovision Dance Contest has been cancelled indefinitely.

Supporting paragraphs: Finland in the Eurovision Dance Contest Tango
Answer: River Plata