Although Jerusalem’s most famous structures are quite old, much of the city’s modern look was given it by three architects: Erich Mendelsohn (a Jewish refugee from Nazi Germany), Austen St. Barbe Harrison (the official architect of the British Mandate), and Spyro Houris (a Greek Orthodox Arab). They are the subject of a new book, Till We Have Built Jerusalem: Architects of a New City, by Adina Hoffman, which she discusses here. (Interview by Sara Ivry; audio, 43 minutes.)

Concluded in 1979, the Israeli-Egyptian peace treaty ended nearly 30 years of intermittent warfare, and proved one of the most enduring and beneficial products of Middle East diplomacy. But Egypt may not have been upholding its end of the bargain, write Jonathan Schanzer and Mariam Wahba:

Article III, subsection two of the peace agreement’s preamble explicitly requires both parties “to ensure that that acts or threats of belligerency, hostility, or violence do not originate from and are not committed from within its territory.” This clause also mandates both parties to hold accountable any perpetrators of such acts.

Recent Israeli operations along the Philadelphi Corridor, the narrow strip of land bordering Egypt and Gaza, have uncovered multiple tunnels and access points used by Hamas—some in plain sight of Egyptian guard towers. While it could be argued that Egypt has lacked the capacity to tackle this problem, it is equally plausible that it lacks the will. Either way, it’s a serious problem.

Was Egypt motivated by money, amidst a steep and protracted economic decline in recent years? Did Cairo get paid off by Hamas, or its wealthy patron, Qatar? Did the Iranians play a role? Was Egypt threatened with violence and unrest by the Sinai’s Bedouin Union of Tribes, who are the primary profiteers of smuggling, if it did not allow the tunnels to operate? Or did the Sisi regime take part in this operation because of an ideological hatred of Israel?