Final answer:
The Spanish Civil War lasted for 3 years (1936-1939), the construction of El Valle de los Caídos took around 18 years (1940-1958), and there are over 33,000 soldiers buried there. The total number of years when adding the duration of the war and the time taken to construct the site is 21 years; the number of buried soldiers is an additional fact.
Step-by-step explanation:
The Spanish Civil War lasted from 1936 to 1939, which is a span of 3 years. The monumental site known as The Valley of the Fallen, or El Valle de los Caídos, took approximately 18 years to construct, from 1940 to 1958. Regarding the total number of soldiers buried at El Valle de los Caídos, it is believed to be over 33,000, although exact figures are disputed due to the nature of the internments. To answer your question, we start by adding the number of years for each event, which is quite straightforward: 3 years for the war duration plus 18 years for the construction of the valley, giving us 21 years. However, summarizing the total number of soldiers buried in a numerical answer is more complex and cannot be added to the previous total as it is not measured in years.
Therefore, combining these figures into one summation, you would have 21 years, which refers to the time-related questions, and beyond that, a note that over 33,000 soldiers are buried at the site, which is a separate fact altogether. Hopefully, this clarifies your question on how to tackle the summation of years and gives additional context to the noteworthy figures associated with El Valle de los Caídos.