The Mole of Argier was the main concern of the Diary, beginning 1 February 1661/62 http://www.pepysdiary.com/diary/1662/02/01/
Pedro. on Wed 2 Feb 2005, 9:20 am | Link
"mole of Argier”
The inner harbour was begun in 1518 by Khair-ad-Din Barbarossa (see History, below), who, to accommodate his pirate vessels, caused the island on which was Fort Penon to be connected with the mainland by a mole. The lighthouse which occupies the site of Fort Penon was built in 1544.
Argier (Algier): http://www.pepysdiary.com/encyclopedia/3088/
Chris Squire • Link
‘mole, n.2 . . Middle French mole in uses corresponding to sense 2 is probably not immediately < Latin, but, as indicated by the gender, probably arises ultimately from Byzantine Greek μῶλος , μόλος (6th cent.; < classical Latin mōlēs ), which was probably borrowed into Italian as molo (a1313;
. . 2. A massive structure, esp. of stone, serving as a pier, breakwater, or causeway. Also: the area of water bounded by or contained within such a structure, esp. forming a harbour or port.
1545 in Acts Privy Council 8 Sept. (1890) I. 241 Letters to Boloyne for the making of a Jettye or Mole.
. . 1632 W. Lithgow Totall Disc. Trav. x. 448 A French ship‥that was lying in the Mould.
1641 L. Roberts Treasure of Traffike in J. R. McCulloch Early Eng. Tracts Comm. (1952) ii. 100 Hee erected a watch-Tower with a strong mould to preserve the ships that anchor there from the violence of all weathers.
. . 1727 A. Hamilton New Acct. E. Indies I. vi. 53 It has‥a pretty good Mould, or Bason, for the Easterly [monsoons].’ [OED]
Chart showing the number of references in each month of the diary’s entries.