Two 24-hour strikes will essentially shut down the London Underground rail network beginning at 8 p.m. Sept. 24 and again at 8 p.m. Oct. 1. Find alternative transit and be prepared for inconveniences.

An effort to reduce traffic congestion in London’s city center has run afoul of the U.S. Embassy and threatens to generate a tit-for-tat squabble between the two allies. London’s mayor has signed a law to charge motorists $7 to drive into the eight-square-mile heart of the city, but this amounts to a tax, U.S. diplomats say, and taxing foreign diplomats violates the Geneva Convention of 1961. The mayor, however, says this is a road charge, not a tax. The embassy has threatened to levy a reciprocal charge on British diplomats in Washington. However this spat is resolved, non-diplomats will certainly be charged $7 to drive into central London.