The image used for the Palazzo Salis is the wrong one, as this shows the one at Soglio. The Countess lived at the Palazzo Salis at Bondo. I would be happy to provide you with an image of the same. You will find quite a number of views on the internet, such as this one

Mildred Acheson, Countess of Gosford (born Caroline Mildred Carter) (March 2, 1888 – September 7, 1965) was an American heiress who married into the British aristocracy.

Mildred was born on March 2, 1888, in Cambridge, Massachusetts.^[1] Millie, as she was also known, was the only daughter of diplomat John Ridgeley Carter (1864–1944) and Alice (née Morgan) Carter (1865–1933).^[2] Her younger brother was banker Bernard Shirley Carter, a prominent banker with Morgan, Harjes & Co. who married Louise Hope Thacher.^[3]

Her paternal grandparents were Mary Buckner (née Ridgely) Carter and Bernard Carter, a member of the prominent Carter and Lee families of Virginia and was a descendant of Henry Lee III, the 9th Governor of Virginia. Her maternal grandparents were David Pierce Morgan and Carolyn (née Fellowes) Morgan. Her maternal uncle was William Fellowes Morgan Sr. and among her first cousins was William Fellowes Morgan Jr.

Her father was a diplomat of the United States, serving as the First Secretary to the American Embassy in London.^[4] Later, he served as the U.S. Minister at Bucharest from November 14, 1909, until October 24, 1911. He also concurrently served as the U.S. Minister to Serbia and Bulgaria.^[5]

In May 1908, noted American portrait painter John Singer Sargent painted a portrait of Mildred in London that was described at the time by The New York Times as "in the painter's best manner and brings out all of the innate sweetness of nature which has endeared Miss Carter to her English as much as to her American friends, all of whom agree that she has the wonderful tact and urbanity of her father."^[6] She was presented at the Court of St James's in 1909.^[1]

The picture shown is of the Hotel Plazzo Salis in nearby Soglio. My grandmother spent summers from 1949to 1965 in the Palazzo Salis in Bondo, which she rented from the Salis family.

On June 21, 1910,^[7] Mildred was married to Archibald Acheson, Viscount Acheson at St George's Hanover Square Church in London followed by a reception at Dorchester House.^{[lower-alpha 1]} The Viscount Acheson was the eldest son, and eventual heir, of Archibald Acheson, 4th Earl of Gosford and Lady Louisa Montagu, a Lady-in-Waiting to Queen Alexandra.^[9] His paternal grandfather was Archibald Acheson, 3rd Earl of Gosford and his maternal grandparents were William Montagu, 7th Duke of Manchester and the former Countess Louisa von Alten.^[9] Together, Mildred and Archibald were the parents of the five children:^[9]

• Archibald Alexander John Stanley Acheson, 6th Earl of Gosford (1911–1966), who married Francesca Cagiati, eldest daughter of Francesco Cagiati.^[10] They divorced in 1960 and he remarried to Cynthia Margaret Delius, the widow of Maj. James Pringle Delius and daughter of Capt. Henry Cave West MC.^[9]
• Lady Patricia Acheson (1911–1915), a twin who died in childhood.^[9]
• Hon. Patrick Bernard Victor Montagu Acheson (1915–2005), who married Judith Gillette, a daughter of Earle P. Gillette.^[9]
• Lady Mildred Camilla Nichola Acheson (1917–1988), who married Baron Hans Christoph Freiherr Schenk von Stauffenberg in 1937. She later married Axel Freiherr von dem Bussche-Streithorst in 1950.^[9]
• Lady Mary Virginia Shirley Acheson (1919–1996), who married Fernando Corcuera in Mexico in 1941.^[9]

Viscount Acheson's father died in 1922 (shortly after selling the family seat Gosford Castle) and he succeeded to the earldom of Gosford. Five years later in 1927, the couple separated and Lord Gosford went to New York City.^[11] The Countess of Gosford obtained a divorce in December 1927,^[12] and he remarried to Beatrice (née Claflin) Breese,^[13] a granddaughter of merchant Horace Brigham Claflin, on October 1, 1928.^[14]

Mildred died on September 7, 1965, at Palazzo Salis, her home in Bondo, Switzerland.^[1]