<figure class="puerta x">
  <figcaption>Css a Fondo</figcaption>
  <img src="https://4.bp.blogspot.com/-meAG8mj-VNU/UUnGnKM6iMI/AAAAAAAAGco/ijPN3xTsiSg/s1600/revelar-x.jpg" alt="">
  <img src="https://4.bp.blogspot.com/-meAG8mj-VNU/UUnGnKM6iMI/AAAAAAAAGco/ijPN3xTsiSg/s1600/revelar-x.jpg" alt="">
</figure>

<figure class="puerta y">
  <figcaption><span>Las Arribes</span> del Río Duero en "La Raya" de Salamanca y Zamora con Portugal.
  <a href="https://twitter.com/search?q=%23arribesquierevida">#ArribesQuiereVida</a>
  </figcaption>
  <img src="https://2.bp.blogspot.com/-EMMxQRG7bwc/UUnGmu3Q6WI/AAAAAAAAGck/5w38nkTha-A/s1600/revelar-y.jpg" alt="">
  <img src="https://2.bp.blogspot.com/-EMMxQRG7bwc/UUnGmu3Q6WI/AAAAAAAAGck/5w38nkTha-A/s1600/revelar-y.jpg" alt="">
</figure>

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