Test Matches at the Same Venue in a Series

Pakistan vs Zimbabwe test series consists of 2 Test matches and both being played at Harare. 

How unique is this ? 
There have been only 4 other 2 match test series which had both matches played on the same venue.

1876-77 Aus vs Eng, both matches at MCG 
1886-87 Aus vs Eng, both matches at SCG 
2001-02 Pak vs WI, both matches at Sharjah
2012-13 Ban vs Zim, both matches at Harare 
2013 - Pak vs Zim, both matches at Harare

In all, this is the 18th test series, irrespective of number of matches in the series, where 2 matches are played on the same venue.

And only 1 series in Cricket History had 3 matches played at the same venue, the Eng vs SA, 1905-06, a 5 match series in which 3 were played at Johannesburg and 2 at Cape Town. 

List of Test Series, where 2 or more matches were played at the same venue

01. 1876-77, Aus v Eng, Melbourne
02. 1881-82, Aus v Eng, Sydney
03. 1882-83, Aus v Eng, Melbourne
04. 1882-83, Aus v Eng, Sydney
05. 1884-85, Aus v Eng, Sydney
06. 1886-87, Aus v Eng, Sydney
07. 1902-03, SA v Aus, Johannesburg
08. 1905-06, SA v Eng, Cape Town
09. 1909-10, SA v Eng, Cape Town
10. 1913-14, SA v Eng, Johannesburg
11. 1929-30, NZ v Eng, Auckland
12. 1975-76, WI v Ind, Port-of-Spain
13. 1997-98, WI v Eng, Port-of-Spain
14. 1990-00, Zim v SL, Harare
15. 2001-02, Pak v WI, Sharjah
16. 2002-03, Pak v Aus, Sharjah
17. 2013, Zim v Ban, Harare

18. 2013, Zim vs Pak, Harare