This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

On July 11, 1877, a few days after the Bell Telephone Company was established, Bell married Mabel Hubbard (1857–1923) at the Hubbard estate in Cambridge, Massachusetts. His wedding present to his bride was to turn over 1,487 of his 1,497 shares in the newly formed Bell Telephone Company. Shortly thereafter, the newlyweds embarked on a year-long honeymoon in Europe. During that excursion, Bell took a handmade model of his telephone with him, making it a "working holiday". The courtship had begun years earlier; however, Bell waited until he was more financially secure before marrying. Although the telephone appeared to be an "instant" success, it was not initially a profitable venture and Bell's main sources of income were from lectures until after 1897. One unusual request exacted by his fiancée was that he use "Alec" rather than the family's earlier familiar name of "Aleck". From 1876, he would sign his name "Alec Bell". They had four children:
Who did Bell marry in 1877?

Solar distillation can be used to make saline or brackish water potable. The first recorded instance of this was by 16th-century Arab alchemists. A large-scale solar distillation project was first constructed in 1872 in the Chilean mining town of Las Salinas. The plant, which had solar collection area of 4,700 m2 (51,000 sq ft), could produce up to 22,700 L (5,000 imp gal; 6,000 US gal) per day and operate for 40 years. Individual still designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect. These stills can operate in passive, active, or hybrid modes. Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.
In what year was a large scale solar distillation project constructed in Las Salinas?

The first lighting used on an airport was during the latter part of the 1920s; in the 1930s approach lighting came into use. These indicated the proper direction and angle of descent. The colours and flash intervals of these lights became standardized under the International Civil Aviation Organization (ICAO). In the 1940s, the slope-line approach system was introduced. This consisted of two rows of lights that formed a funnel indicating an aircraft's position on the glideslope. Additional lights indicated incorrect altitude and direction.

When was the first lighting used on an airport?