puzzle

 ACROSS

  1 Uber offering

  5 Where to find 12 landlocked countries

  9 Dance "for two"

 14 Low-pH substance

 15 Diagram style with overlap

 16 Continent separator, at times

 17 Certain gourmet truffle

 20 Come together

 21 Veggie dip herb

 22 Hi-___ monitor

 23 Former columnist Bombeck

 26 Prestigious prizes

 28 Safe space to tweet?

 32 Nest egg option, briefly

 33 Jump that's harder than a lutz

 34 Swim-bike-run race, for short

 35 Small salamander

 37 Mannequin's headwear

 39 Meadow mamas

 43 Owns

 46 Give shape to

 49 Enjoyed empanadas

 50 Pure chance

 53 Winery visitor

 54 You can dig it

 55 Water, in France

 56 McEntire of country

 58 Everything ___ (deli choice)

 62 1978 hit whose title is sung after "You're once, twice," ... and a hint to the starts of 17-, 28- and 50-Across

 66 Nickel and dime

 67 Garr of "Young Frankenstein"

 68 On any occasion

 69 Takes, as advice

 70 Flip out

 71 Russo who played Frigga


DOWN

  1 Prego alternative

  2 Smartphone symbol

  3 Conn of "Grease"

  4 Changed the language of?

  5 Director DuVernay

  6 Jiffy

  7 How many TV shows air

  8 Consecrate with oil

  9 Office strip?

 10 Knee injury initials

 11 Almost

 12 Stadium entry points

 13 Singles

 18 "... and vice ___"

 19 Social influence

 24 Upper bound, familiarly

 25 Once more

 27 Cedar Point's lake

 28 Storage container

 29 Feeling after a driver cuts you off

 30 Uncooked

 31 Steep face

 36 Therefore

 38 Person who often wears dark makeup

 40 Major conflict

 41 Incoming flight stat

 42 Repair a teddy bear, perhaps

 44 Certain cast member

 45 Sport with clay disks

 47 Pi follower

 48 Kind of toast

 50 Hugh who made "House" calls?

 51 Planets' paths

 52 Casino employee

 53 Lake in the Golden and Silver states

 55 Engrave

 57 "I agree 100%!"

 59 Donated

 60 Biblical paradise

 61 Ancient stringed instrument

 63 Conclusion

 64 Page of history

 65 Small drink

solution