Mont Blanc (BrE: /ˌmɒˈblɒ(k)/; AmE: /ˌmɑːn(t)ˈblɑːŋk/; French: Mont Blanc [mɔ̃ blɑ̃]; Italian: Monte Bianco [ˈmonte ˈbjaŋko], both meaning "white mountain") is the highest mountain in the Alps and Western Europe, and the highest mountain in Europe outside the Caucasus mountains, rising 4,805.59 m (15,766 ft) above sea level, located on the French-Italian border. It is the second-most prominent mountain in Europe, after Mount Elbrus, and it is the eleventh most prominent mountain summit in the world.

The Rigi (or Mount Rigi; also known as Queen of the Mountains) is a mountain massif of the Alps, located in Central Switzerland. The whole massif is almost entirely surrounded by the water of three different water bodies: Lake Lucerne, Lake Zug and Lake Lauerz. The range is in the Schwyzer Alps, and is split between the cantons of Schwyz and Lucerne, although the main summit, named Rigi Kulm, at 1,798 meters above sea level, lies within the canton of Schwyz.
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The Matterhorn  is a mountain of the Alps, straddling the main watershed and border between Switzerland and Italy.

The name Jungfrau ("maiden, virgin"), which refers to the highest of the three prominent mountains overlooking the Interlaken region, along with the Mönch ("monk") and the Eiger ("ogre"), is most likely derived from the name Jungfrauenberg given to Wengernalp, the alpine meadow directly facing the huge northern side of the Jungfrau, across the Trummelbach gorge. Wengernalp was so named for the nuns of Interlaken Monastery, its historical owner.

Mount Ebal (Arabic: جبل عيبال‎ Jabal ‘Aybāl; Hebrew: הר עיבל‎ Har ‘Eival) is one of the two mountains in the immediate vicinity of the Palestinian city of Nablus in the West Bank (biblical Shechem), and forms the northern side of the valley in which Nablus is situated, the southern side being formed by Mount Gerizim. The mountain is one of the highest peaks in the West Bank and rises to 3084 feet (940 meters) above sea level, some 194 feet (59 meters) higher than Mount Gerizim.

Mount Gerizim (pron.: /ˈɡɛrɨˌzɪm/; Samaritan Hebrew Ar-garízim, Arabic جبل جرزيم Jabal Jarizīm, Tiberian Hebrew הַר גְּרִזִּים Har Gərizzîm, Standard Hebrew הַר גְּרִיזִּים Har Gərizzim) is one of the two mountains in the immediate vicinity of the West Bank city of Nablus (biblical Shechem), and forms the southern side of the valley in which Nablus is situated, the northern side being formed by Mount Ebal. The mountain is one of the highest peaks in the West Bank and rises to 2849 feet (881 m) above sea level, 228 feet (69.5 m) shorter than Mount Ebal.

The Blue Mountains is a mountainous region in New South Wales, Australia. It borders on Sydney's metropolitan area, its foothills starting about 50 kilometres (31 mi) west of the state capital.[2] The public's understanding of the extent of the Blue Mountains is varied, as it forms only part of an extensive mountainous area associated with the Great Dividing Range.

The Hornisgrinde, 1,164 m (3,820 ft), is the highest mountain in the Northern Black Forest of Germany. The Hornisgrinde lies in northern Ortenaukreis district.

The Harz is a Mittelgebirge that has the highest elevations in Northern Germany and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart (hill forest), Latinized as Hercynia. The Brocken is the highest summit in the Harz with an elevation of 1,141.1 metres (3,744 ft) above sea level. The Wurmberg (971 metres (3,186 ft)) is the highest peak located entirely within the state of Lower Saxony. https://en.wikipedia.org/wiki/Harz

Apes' Hill, Pillars of Hercules

Jebel Musa (Arabic: جبل موسى‎, Jabal Mūsā, in Berber Adrar n Moussa; meaning Mount Moses) is a mountain in the northernmost part of Morocco, on the African side of the Strait of Gibraltar. It is part of the Rif mountain chain. The mountain is generally identified as the southern Pillar of Hercules, Abila Mons.
https://en.wikipedia.org/wiki/Jebel_Musa_(Morocco)

Mount Ida (Turkish: Kazdağı, pronounced [kazdaːɯ], meaning "Goose Mountain",[1] Kaz Dağları, or Karataş Tepesi) is a mountain in northwestern Turkey, some 20 miles southeast of the ruins of Troy, along the north coast of the Gulf of Edremit. The name Mount Ida is the ancient one. It is between Balıkesir Province and Çanakkale Province.

https://en.wikipedia.org/wiki/Mount_Ida_(Turkey)

This is possibly what Twain was referring to as Pentilicon

Hymettus, also Hymettos (pronounced /haɪˈmɛtəs/ in English, Greek: Υμηττός, transliterated Ymīttós, pronounced [imiˈtos]) is a mountain range in the Athens area, East Central Greece. It is also colloquially known as Trellós or Trellóvouno (crazy mountain), a name of uncertain origin. In antiquity there was a sanctuary to Zeus Ombrios (Zeus the Rain God) on the summit with numerous offerings dating especially to the 8th-7th centuries BC; they are on the site of a military base and not currently accessibe.

The Alban Hills (Italian Colli Albani) are the site of a quiescent volcanic complex in Italy, located 20 km (12 mi) southeast of Rome and about 24 kilometres (15 mi) north of Anzio.
The dominant peak (but not the highest) is Monte Cavo at 950 m. There are two small calderas which contain lakes, Lago Albano and Lake Nemi. The rock of the hills is called Peperino (lapis albanus) a particular Tuff, a combination of ash and small rocks that is useful for construction, and provides a mineral-rich substrate for grape vines.

The mountains lend their name to the Apennine peninsula that forms the major part of Italy.[5] They are mostly verdant, although one side of the highest peak, Corno Grande, is partially covered by Calderone glacier, the only glacier 

Mount Lebanon (Arabic: جبل لبنان‎; Jabal Lubnān, Syriac: ܛܘܪ ܠܒܢܢ; ṭūr lébnon), as a geographic designation, is a Lebanese mountain range, averaging above 2,200 meters in height and receiving a substantial amount of precipitation, including snow, which averages around four meters deep. It extends across the whole country along about 170 km (110 mi), parallel to the Mediterranean coast with the highest peak, Qurnat as Sawda', at 3,088 m (10,131 ft). Lebanon has historically been defined by these mountains, which provided protection for the local population.